Buick Regal 1997-2000

Cylinder Head

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There are two basic types of cylinder heads used on the vehicles covered by this manual: the Over Head Valve (OHV, also called a Pushrod Engine) (3.1L VIN M, 3.4L VIN E, 3.8L VIN 1 and 3.8L VIN K) and the Over Head Camshaft (OHC) (in this case, Dual Over Head Camshaft which, on these V6 engines, use a total of four camshafts) which are the 3.4L VIN X and 3.5L VIN H.

Most cylinder heads are made of an aluminum alloy due to its light weight, durability and heat transfer qualities. However, cast iron is still used on many vehicles today. Whether made from aluminum or iron, all cylinder heads have valves and seats. Some use two valves per cylinder, while the more hi-tech engines will utilize a multi-valve configuration using 4 valves per cylinder. When the valve contacts the seat, it does so on precision machined surfaces, which seals the combustion chamber. All cylinder heads have a valve guide for each valve. The guide centers the valve to the seat and allows it to move up and down within it. The clearance between the valve and guide can be critical. Too much clearance and the engine may consume oil, lose vacuum and/or damage the seat. Too little, and the valve can stick in the guide causing the engine to run poorly if at all, and possibly causing severe damage. The last component all cylinder heads have are valve springs. The spring holds the valve against its seat. It also returns the valve to this position when the valve has been opened by the valve train or camshaft. The spring is fastened to the valve by a retainer and valve locks (sometimes called keepers). Aluminum heads will also have a valve spring shim to keep the spring from wearing away the aluminum.

An ideal method of rebuilding the cylinder head would involve replacing all of the valves, guides, seats, springs, etc., with new parts. However, depending on how the engine was maintained, this might not be not necessary. Springs fall victim to the driving habits of the individual. A driver who often runs the engine rpm to the redline will wear out or break the springs faster then one that stays well below it. Unfortunately, mileage takes it toll on all of the parts. Generally, the valves, guides, springs and seats in a cylinder head can be machined and re-used, saving you money. However, if a valve is burnt, it may be wise to replace all of the valves, since they were all operating in the same environment. The same goes for any other component on the cylinder head. Think of it as an insurance policy against future problems related to that component.

Unfortunately, the only way to find out which components need replacing, is to disassemble and carefully check each piece. After the cylinder head(s) are disassembled, thoroughly clean all of the components.

Overhaul



Assembly

The first step for any assembly job is to have a clean area in which to work. Next, thoroughly clean all of the parts and components that are to be assembled. Finally, place all of the components onto a suitable work space and, if necessary, arrange the parts to their respective positions.

OHV Engines
  1. Lightly lubricate the valve stems and insert all of the valves into the cylinder head. If possible, maintain their original locations.
  2.  
  3. If equipped, install any valve spring shims which were removed.
  4.  
  5. If equipped, install the new valve seals, keeping the following in mind:

    If the valve seal presses over the guide, lightly lubricate the outer guide surfaces.
     
    If the seal is an O-ring type, it is installed just after compressing the spring but before the valve locks.
     

  6.  
  7. Place the valve spring and retainer over the stem.
  8.  
  9. Position the spring compressor tool and compress the spring.
  10.  
  11. Assemble the valve locks to the stem.
  12.  
  13. Relieve the spring pressure slowly and insure that neither valve lock becomes dislodged by the retainer.
  14.  
  15. Remove the spring compressor tool.
  16.  
  17. Repeat Steps 2 through 8 until all of the springs have been installed.
  18.  

Rocker Arm Type Camshaft Followers
  1. Lightly lubricate the valve stems and insert all of the valves into the cylinder head. If possible, maintain their original locations.
  2.  
  3. If equipped, install any valve spring shims which were removed.
  4.  
  5. If equipped, install the new valve seals, keeping the following in mind:

    If the valve seal presses over the guide, lightly lubricate the outer guide surfaces.
     
    If the seal is an O-ring type, it is installed just after compressing the spring but before the valve locks.
     

  6.  
  7. Place the valve spring and retainer over the stem.
  8.  
  9. Position the spring compressor tool and compress the spring.
  10.  
  11. Assemble the valve locks to the stem.
  12.  
  13. Relieve the spring pressure slowly and insure that neither valve lock becomes dislodged by the retainer.
  14.  
  15. Remove the spring compressor tool.
  16.  
  17. Repeat Steps 2 through 8 until all of the springs have been installed.
  18.  
  19. Install the camshaft(s), rockers, shafts and any other components that were removed for disassembly.
  20.  

Cleaning & Inspecting

Now that all of the cylinder head components are clean, it's time to inspect them for wear and/or damage. To accurately inspect them, you will need some specialized tools:



A 0-1 in. micrometer for the valves
 
A dial indicator or inside diameter gauge for the valve guides
 
A spring pressure test gauge
 

If you do not have access to the proper tools, you may want to bring the components to a shop that does.

There are several things to check on the cylinder head: valve guides, seats, cylinder head surface flatness, cracks and physical damage.

Checking The Cylinder Head For Warpage (Flatness)

Engine performance and life depends a great deal on how well the cylinder head gasket seals to the engine block. There are number of concerns when it appears a cylinder head needs to be removed.

Make sure that the valve train components are kept together when disassembling the cylinder head. Identify the valve train components. Any valve train components that are being reused must be installed in their original locations.

If the head is be overhauled, remove any remaining components such as the engine lift hook, the fuel line bracket bolts, the engine coolant temperature sensor, etc., as required.

If the head gasket failed, determine the cause. Gasket failure is caused by the following conditions: improper installation; loose or warped cylinder head; missing, off location or not fully seated locator dowel pins; low torque on the cylinder head bolts; warped block surface; scratched or gouged gasket surfaces; excessive intake manifold torque and even cracked engine block tapped holes.

Clean all parts well. Remove all foreign material to the bare metal. Do not use a motorized wire brush on any gasket sealing surface.

Clean all threaded holes with a thread-cutting tap to remove rust, old sealer or thread-locking compound and other debris. Use care when using a tap on aluminum parts. Thread the tap in by hand to start so not enough leverage can be applied to damage threads if the tap is started incorrectly.

Inspect the cylinder head for cracks. Check between the valve seats and inspect the inside of the exhaust ports. Inspect the cylinder head for corrosion. Do not attempt to weld the cylinder head. If the head is damaged, it must be replaced.

Inspect the following locations for flatness: the cylinder head deck and the intake and exhaust manifold mating surfaces. Within limits, a head can be reconditioned at an automotive machine shop using a milling machine. On the engines covered by this product, replace the head if more than 0.010 inch (0.254mm) must be removed to true up the head.

Inspect all of threaded holes for damage. If necessary repair the holes with threaded inserts, if possible. If not, replace the head.

Inspect the cooling jacket plugs (sometimes called freeze plugs). Normally, these should be replaced when a head is removed since access to them once assembled in the vehicle is usually impossible.

If you have the equipment to remove the valve springs, the head can be completely disassembled and the valve seats checked. In most all cases, even professionals technicians leave this job to an automotive machine shop. In many cases, a worn cylinder head can be exchanged for a reconditioned head, saving time and money.


WARNING
It is difficult to over-emphasize the need to use care when working on an aluminum cylinder head. Any light alloy head is easily damaged and will be expensive to replace. Protect the gasket sealing surfaces. Do not use a caustic solvent on aluminum. Do not use a power-drive wire brush or other abrasive pad on an aluminum head. Hand all aluminum parts with care.

  1. With the valves still in place to protect the valve seats, remove the carbon deposits from the combustion chambers and valve heads. Use care. If the head is made of cast iron, a drill-mounted wire brush can be used. Do not use a wire brush on an aluminum head. Use care not to damage the gasket surfaces. If the head is be disassembled, proceed to Step 3. If the head is not to be disassembled, proceed to Step 2.
  2.  
  3. Remove all dirt, oil and old gasket material from the cylinder head with a suitable solvent such as Safety-Kleen®. Clean all the bolt holes and oil and coolant passages. Use care to keep solvent off the valve seals as the solvent may damage them. Dry the cylinder head with compressed air, if available. Check the head for cracks or other damage, and check the gasket surface for burrs, nicks and flatness. If you are in doubt about the head's serviceability, consult a reputable automotive machine shop.
  4.  
  5. If you have the equipment available, remove the valves, springs and retainers, then clean the valve guide bores with a valve guide cleaning tool. Remove all dirt, oil and gasket material from the cylinder head with a suitable such as Safety-Kleen®. Clean the bolt holes and the oil and coolant passages.
  6.  
  7. Remove all deposits from the valves with a wire brush of buffing wheel. Inspect the valves as described later in this section.
  8.  
  9. Check the head for cracks using a dye penetrant in the valve seat area and port, head surfaces and top. Check the gasket surface for burrs, nicks and flatness. If you are in doubt about the head's serviceability, consult a reputable automotive machine shop.
  10.  


NOTE
If the cylinder head was removed to replace a blown head gasket due to an overheating condition and a crack is suspected, do not assume the head is not cracked because a crack is visually found. A crack can be so small that it cannot be seen by eye, but can pass coolant when the engine is at operating temperature. Consult an automotive machine shop that has testing equipment to make sure the head is not cracked.

After you have cleaned the gasket surface of the cylinder head of any old gasket material, check the head for flatness.



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Fig. Check the head for flatness across the center of the head surface using a straightedge and feeler gauge



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Fig. Checks should also be made along both diagonals of the head surface

Place a straightedge across the gasket surface. Using feeler gauges, determine the clearance at the center of the straightedge and across the cylinder head at several points. Check along the centerline and diagonally on the head surface. If the warpage exceeds 0.003 in. (0.076mm) within a 6.0 in. (15.2cm) span, or 0.006 in. (0.152mm) over the total length of the head, the cylinder head must be resurfaced. After resurfacing the heads of a V-type engine, the intake manifold flange surface should be checked, and if necessary, milled proportionally to allow for the change in its mounting position.

Certain cracks can be repaired in both cast iron and aluminum heads. For cast iron, a tapered threaded insert is installed along the length of the crack. Aluminum can also use the tapered inserts, however welding is the preferred method. Some physical damage can be repaired through brazing or welding. Contact a machine shop to get expert advice for your particular dilemma.

Cracks & Physical Damage

Generally, cracks are limited to the combustion chamber, however, it is not uncommon for the head to crack in a spark plug hole, port, outside of the head or in the valve spring/rocker arm area. The first area to inspect is always the hottest: the exhaust seat/port area.

A visual inspection should be performed, but just because you don't see a crack does not mean it is not there. Some more reliable methods for inspecting for cracks include Magnaflux®, a magnetic process or Zyglo®, a dye penetrant. Magnaflux®is used only on ferrous metal (cast iron) heads. Zyglo® uses a spray on fluorescent mixture along with a black light to reveal the cracks. It is strongly recommended to have your cylinder head checked professionally for cracks, especially if the engine was known to have overheated and/or leaked or consumed coolant. Contact a local shop for availability and pricing of these services.

Physical damage is usually very evident. For example, a broken mounting ear from dropping the head or a bent or broken stud and/or bolt. All of these defects should be fixed or, if unrepairable, the head should be replaced.

Valve Seats

A visual inspection of the valve seats should show a slightly worn and pitted surface where the valve face contacts the seat. Inspect the seat carefully for severe pitting or cracks. Also, a seat that is badly worn will be recessed into the cylinder head. A severely worn or recessed seat may need to be replaced. All cracked seats must be replaced. A seat concentricity gauge, if available, should be used to check the seat run-out. If run-out exceeds specifications the seat must be machined (if no specification is given use 0.002 in. or 0.051mm).

Disassembly
3.1L, 3.4L (VIN E) And 3.8L Engines

Before disassembling the cylinder head, you may want to fabricate some containers to hold the various parts, as some of them can be quite small (such as keepers) and easily lost. Also keeping yourself and the components organized will aid in assembly and reduce confusion. Where possible, try to maintain a components original location; this is especially important if there is not going to be any machine work performed on the components.

  1. If you haven't already removed the rocker arms do so now.
  2.  
  3. Position the head so that the springs are easily accessed.
  4.  



Click image to see an enlarged view

Fig. When removing an OHV valve spring, use a compressor tool to relieve the tension from the retainer

  1. Use a valve spring compressor tool, and relieve spring tension from the retainer.
  2.  


NOTE
Due to engine varnish, the retainer may stick to the valve locks. A gentle tap with a hammer may help to break it loose.



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Fig. A small magnet will help in removal of the valve locks



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Fig. Be careful not to lose the small valve locks (keepers)

  1. Remove the valve locks from the valve tip and/or retainer. A small magnet may help in removing the locks.
  2.  
  3. Lift the valve spring, tool and all, off of the valve stem.
  4.  



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Fig. Remove the valve seal from the valve stem-O-ring type seal shown



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Fig. Removing an umbrella/positive type seal

  1. If equipped, remove the valve seal. If the seal is difficult to remove with the valve in place, try removing the valve first, then the seal. Follow the steps below for valve removal.
  2.  



Click image to see an enlarged view

Fig. Invert the cylinder head and withdraw the valve from the valve guide bore

  1. Position the head to allow access for withdrawing the valve.
  2.  


NOTE
Cylinder heads that have seen a lot of miles and/or abuse may have mushroomed the valve lock grove and/or tip, causing difficulty in removal of the valve. If this has happened, use a metal file to carefully remove the high spots around the lock grooves and/or tip. Only file it enough to allow removal.

  1. Remove the valve from the cylinder head.
  2.  
  3. If equipped, remove the valve spring shim. A small magnetic tool or screwdriver will aid in removal.
  4.  
  5. Repeat Steps 3 though 9 until all of the valves have been removed.
  6.  

3.4L (VIN X) And 3.5L Engines

Use care when working on these heads. The aluminum alloy is relative soft and easily damaged. Pay attention to careful labeling of the parts on the dual camshaft cylinder head. There will be an intake camshaft and followers as well as an exhaust camshaft and followers and they must be labeled as such. In some cases, the components are identical and could easily be installed incorrectly. DO NOT MIX THEM UP! Determining which is which is very simple; the intake camshaft and components are on the same side of the head as was the intake manifold; the exhaust camshaft and components are on the same side of the head as was the exhaust manifold.



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Fig. Exploded view the cylinder head and components on a DOHC engine-3.4L (VIN X) engine shown



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Fig. Example of a multi-valve cylinder head. Note how it has 2 intake and 2 exhaust valve ports



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Fig. This type of spring compressor and adapter can be used on OHC engines



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Fig. The camshafts are retained by bearing caps similar to this



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Fig. Using a spring compressor on a DOHC head

Camshaft Followers

Most cylinder heads with rocker arm-type camshaft followers are easily disassembled using a standard valve spring compressor. However, certain models may not have enough open space around the spring for the standard tool and may require you to use a C-clamp style compressor tool instead.

  1. If not already removed, remove the rocker arms and/or shafts and the camshaft. If applicable, also remove the hydraulic lash adjusters. Mark their positions for assembly.
  2.  
  3. Position the cylinder head to allow access to the valve spring.
  4.  
  5. Use a valve spring compressor tool to relieve the spring tension from the retainer.
  6.  


NOTE
Due to engine varnish, the retainer may stick to the valve locks. A gentle tap with a hammer may help to break it loose.

  1. Remove the valve locks from the valve tip and/or retainer. A small magnet may help in removing the small locks.
  2.  
  3. Lift the valve spring, tool and all, off of the valve stem.
  4.  
  5. If equipped, remove the valve seal. If the seal is difficult to remove with the valve in place, try removing the valve first, then the seal. Follow the steps below for valve removal.
  6.  
  7. Position the head to allow access for withdrawing the valve.
  8.  


NOTE
Cylinder heads that have seen a lot of miles and/or abuse may have mushroomed the valve lock grove and/or tip, causing difficulty in removal of the valve. If this has happened, use a metal file to carefully remove the high spots around the lock grooves and/or tip. Only file it enough to allow removal.

  1. Remove the valve from the cylinder head.
  2.  
  3. If equipped, remove the valve spring shim. A small magnetic tool or screwdriver will aid in removal.
  4.  
  5. Repeat Steps 3 though 9 until all of the valves have been removed.
  6.  

Refinishing & Repairing

Many of the procedures given for refinishing and repairing the cylinder head components must be performed by a machine shop. Certain steps, if the inspected part is not worn, can be performed yourself inexpensively. However, you spent a lot of time and effort so far, why risk trying to save a small amount of money if you might have to do it all over again-

Most refinishing procedures dealing with the cylinder head must be performed by a machine shop. Read the sections below and review your inspection data to determine whether or not machining is necessary.

Cylinder Head Surface

If the cylinder head is warped, it must be machined flat. If the warpage is extremely severe, the head may need to be replaced. In some instances, it may be possible to straighten a warped head enough to allow machining. In either case, contact a professional machine shop for service.


NOTE
Any OHC cylinder head that shows excessive warpage should have the camshaft bearing journals align bored after the cylinder head has been resurfaced.


WARNING
Failure to align bore the camshaft bearing journals could result in severe engine damage including but not limited to: valve and piston damage, connecting rod damage, camshaft and/or crankshaft breakage.

Springs, Retainers & Valve Locks

There is no repair or refinishing possible with the springs, retainers and valve locks. If they are found to be worn or defective, they must be replaced with new (or known good) parts.

Valve Guides

NOTE
If any machining or replacements are made to the valve guides, the seats must be machined.

Unless the valve guides need machining or replacing, the only service to perform is to thoroughly clean them of any dirt or oil residue.

There are only two types of valve guides used on automobile engines: the replaceable-type (all aluminum heads) and the cast-in integral-type (most cast iron heads). There are four recommended methods for repairing worn guides.



Knurling
 
Inserts
 
Reaming oversize
 
Replacing
 

Knurling is a process in which metal is displaced and raised, thereby reducing clearance, giving a true center, and providing oil control. It is the least expensive way of repairing the valve guides. However, it is not necessarily the best, and in some cases, a knurled valve guide will not stand up for more than a short time. It requires a special knurling tool and precision reaming tools to obtain proper clearances. It would not be cost effective to purchase these tools, unless you plan on rebuilding several of the same cylinder head.

Installing a guide insert involves machining the guide to accept a bronze insert. One style is the coil-type which is installed into a threaded guide. Another is the thin-walled insert where the guide is reamed oversize to accept a split-sleeve insert. After the insert is installed, a special tool is then run through the guide to expand the insert, locking it to the guide. The insert is then reamed to the standard size for proper valve clearance.

Reaming for oversize valves restores normal clearances and provides a true valve seat. Most cast-in type guides can be reamed to accept an valve with an oversize stem. The cost factor for this can become quite high as you will need to purchase the reamer and new, oversize stem valves for all guides which were reamed. Oversizes are generally 0.003 to 0.030 in. (0.076 to 0.762mm), with 0.015 in. (0.381mm) being the most common.

To replace cast-in type valve guides, they must be drilled out, then reamed to accept replacement guides. This must be done on a fixture which will allow centering and leveling off of the original valve seat or guide, otherwise a serious guide-to-seat misalignment may occur making it impossible to properly machine the seat.

Replaceable-type guides are pressed into the cylinder head. A hammer and a stepped drift or punch may be used to install and remove the guides. Before removing the guides, measure the protrusion on the spring side of the head and record it for installation. Use the stepped drift to hammer out the old guide from the combustion chamber side of the head. When installing, determine whether or not the guide also seals a water jacket in the head, and if it does, use the recommended sealing agent. If there is no water jacket, grease the valve guide and its bore. Use the stepped drift, and hammer the new guide into the cylinder head from the spring side of the cylinder head. A stack of washers the same thickness as the measured protrusion may help the installation process.

Valve Seats

NOTE
Before any valve seat machining can be performed, the guides must be within factory recommended specifications. If any machining or replacements were made to the valve guides, the seats must be machined.

If the seats are in good condition, the valves can be lapped to the seats, and the cylinder head assembled. See the valves section for instructions on lapping.

If the valve seats are worn, cracked or damaged, they must be serviced by a machine shop. The valve seat must be perfectly centered to the valve guide, which requires very accurate machining.

Valves

Any valves that were not replaced should be refaced and the tips ground flat. Unless you have access to a valve grinding machine, this should be done by a machine shop. If the valves are in extremely good condition, as well as the valve seats and guides, they may be lapped in without performing machine work.

Removal & Installation



3.1L & 3.4L (VIN E) Engines

Before removing a cylinder head, perform a compression test and/or leakdown test to verify is head removal is required.


NOTE
With some minor variations, this procedure can be used on both the left and right cylinder heads.

  1. Raise and safely support the vehicle.
  2.  
  3. Drain the engine coolant and the engine oil. Lower the vehicle.
  4.  
  5. Remove the upper and lower intake manifold using the procedures found in this section.
  6.  
  7. Remove the rocker arm and pushrods using the procedures found in this section.
  8.  
  9. Remove the exhaust crossover pipe.
  10.  
  11. Remove the engine mount strut bracket.
  12.  
  13. If removing the left side (front) head, remove the dipstick tube.
  14.  
  15. Tag for identification, then remove the spark plug wires. Remove the spark plugs. Please see Section 1 for more information.
  16.  
  17. Remove the exhaust manifold using the procedures found in this section.
  18.  
  19. Remove the eight cylinder head bolts, then remove the cylinder head. There are locator pins that align the head to the block. Pull upwards on the head to disengage the pins, then remove the cylinder head to a suitable work area.
  20.  
  21. If the head is be overhauled, remove any remaining components such as the engine lift hook, the fuel line bracket bolts, the engine coolant temperature sensor, etc., as required.
  22.  



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Fig. Unfasten the cylinder head bolts, then remove the head



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Fig. Remove and discard the cylinder head gasket



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Fig. Use a suitable scraper to thoroughly clean the gasket mating surfaces



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Fig. Position a new gasket, install the head, then tighten the bolts in the sequence shown-3.1L engine shown, 3.4L (VIN E) similar

To install:


NOTE
The cylinder head should be cleaned and inspected before installation. Please see the Engine Reconditioning section.

  1. If the head gasket failed, determine the cause. Gasket failure is caused by the following conditions: improper installation; overheating due to a failure in the electric cooling fan system or a leak in the cooling system; loose or warped cylinder head; missing, off location or not fully seated locator dowel pins; low torque on the cylinder head bolts; warped block surface; scratched or gouged gasket surfaces; excessive intake manifold torque and even cracked engine block tapped holes.
  2.  
  3. Clean all parts well. Remove all foreign material to the bare metal. Do not use a motorized wire brush on any gasket sealing surface. It is good practice to use the proper size thread-cutting tap to clean the threaded bolt holes in the block. This helps assure an accurate torque reading.
  4.  
  5. Place a new head gasket on the clean engine block deck surface. Many gaskets will have some sort of marking denoting TOP or THIS SIDE UP. Make sure the gasket sits flat and is not hung up on the locator dowel pins. Use no sealer on the head gasket.
  6.  
  7. Carefully set the cylinder head in place, using care not to damage the gasket. Make certain that the head engages the locator dowel pins that properly position the head.
  8.  
  9. The bolts should be very clean since dirt built-up on the bolt threads makes it difficult to get an accurate torque reading. These are 'torque to yield' bolts which stretch a small amount when tightened; new bolts are always recommended. On a used vehicle, especially a high-mileage vehicle, it may be difficult to determine if the heads have been removed before and how many cycles the bolts have been removed and tightened. New bolts should be part of any cylinder head service. Use GM Sealer #1052080, or equivalent, on the threads of the head bolts and install all eight bolts, finger-tight.
  10.  
  11. With an accurate torque wrench, tighten the bolts gradually, in sequence, working from the center outwards. Final torque should be 33 ft. lbs. (45 Nm), plus an additional 90 degrees (1/4-turn). A torque angle meter is recommended.
  12.  
  13. Install the remaining components in the reverse order of the removal process.
  14.  

3.4L (VIN X) Engine

WARNING
As with many procedures on the 3.4L VIN X DOHC engine, cylinder head removal is a long and complicated task. Be very sure of your diagnosis before attempting to remove the heads on this engine, especially with the engine still in the vehicle. A compression test and/or leakdown test should be performed. A pair of special tools, GM #J 38613-A Camshaft Timing Clamps, is required to hold the camshafts in place once the timing belt is removed and the head bolts loosened. Remember, the valve timing must be reset if the camshaft drive sprockets are removed from their camshafts. Once lost, there are no pins or keys to help you re-establish valve timing. In addition, use care when working with light alloy parts.

Left Side (Front)


Click image to see an enlarged view

Fig. Cylinder head bolt tightening sequence-3.4L (VIN X) engine

  1. Remove the upper and lower intake manifolds, following the procedures given in this section.
  2.  
  3. Remove the left camshaft carrier using the following procedure.
    1. Remove the camshaft timing belt following the procedures given in this section.
    2.  
    3. Disconnect the exhaust crossover pipe and reposition out of the way.
    4.  
    5. Remove the engine mount strut.
    6.  
    7. Remove the front engine lift bracket.
    8.  
    9. The camshaft carrier covers should have been removed as part of the timing belt removal procedure. From shop stock, cut and install six pieces of rubber hose under the camshaft and between the lifters to hold the lifters in the carrier. The exhaust side uses six pieces of tubing 3/16 x 6 inches long. The intake side uses six pieces of tubing 5/32 x 6 inches long.
    10.  
    11. Remove the camshaft carrier mounting bolts and remove the camshaft carrier. Set aside in a safe place. Discard the gasket.
    12.  

  4.  
  5. Remove the left side exhaust manifold following the procedures given in this section.
  6.  
  7. Remove the dipstick tube.
  8.  
  9. Detach the electrical connector from the temperature sending unit.
  10.  
  11. Remove the cylinder head bolts and carefully lift the head from the vehicle.
  12.  

To install:


NOTE
The cylinder head should be cleaned and inspected before installation. Please see the Engine Reconditioning section.

  1. Clean all parts well. Use care when working with light alloy parts not to gouge or scratch the gasket sealing surfaces. Clean the head bolts well. New replacement bolts are recommended. Clean the cylinder block bolt threads. Make sure all of the oil is removed from the bolt holes.
  2.  
  3. Carefully lay a new gasket on the engine block deck. Some brands of gaskets may say TOP or have some other marking indicating the surface that should face the cylinder head. Make sure the gasket sits flat on the block deck.
  4.  
  5. Carefully install the cylinder head to the block. Align any dowel pins or other locators. Install the head bolts and finger-tighten. Tighten gradually and in sequence, working up to 44 ft. lbs. (60 Nm). After achieving final torque, use a torque angle meter to turn the bolts an additional 90 degrees ( 1 / 4 turn).
  6.  
  7. Connect the temperature sensor wire and install the dipstick tube.
  8.  
  9. Install the left exhaust manifold following the procedures given in this section.
  10.  
  11. Install the left camshaft carrier using the following procedure:
    1. Remove the oil from the camshaft carrier to cylinder head bolts, the holes closest to the exhaust manifold.
    2.  
    3. Install a new camshaft carrier gasket.
    4.  

  12.  


WARNING
Remove the oil from the camshaft hold-down tool hole in the carrier before installing and tightening the bolt.

  1. Install J 38613-A or equivalent camshaft hold-down tool. Tighten the bolt to 22 ft. lbs. (30 Nm).
  2.  


NOTE
The use of petroleum jelly (never chassis grease) in the lifter bores, along with the use of the lifter hold-down hoses mentioned above, will help keep the lifters in place.

  1. Install the camshaft carrier to the cylinder head and position the hold-down bolts.
  2.  
  3. Tighten the camshaft carrier bolts to 20 ft. lbs. (27 Nm).
  4.  
  5. Remove the lifter hold-down hoses. Install the front engine lift bracket.
  6.  

  1. Install the lower and upper intake manifold following the procedures given in this section.
  2.  
  3. Install the remaining components in the reverse order of the removal process. Since coolant will run down into the engine oil system when the head is removed, it is most important to drain the engine oil and refill with clean engine oil. A filter change is also recommended.
  4.  

Right Side (Rear)
  1. Remove the upper and lower intake manifolds following the procedures given in this section.
  2.  
  3. Remove the right camshaft carrier using the following procedure.
    1. Remove the camshaft timing belt following the procedures given in this section.
    2.  
    3. The camshaft carrier covers should have been removed as part of the timing belt removal procedure. From shop stock, cut and install six pieces of rubber hose under the camshaft and between the lifters to hold the lifters in the carrier. The exhaust side uses six pieces of tubing 3/16 x 6 inches long. The intake side uses six pieces of tubing 5/32 x 6 inches long.
    4.  
    5. Remove the camshaft carrier mounting bolts and remove the camshaft carrier. Set aside in a safe place. Discard the gasket.
    6.  

  4.  
  5. Remove the exhaust crossover pipe.
  6.  
  7. Raise and suitably support the vehicle.
  8.  
  9. Disconnect the front exhaust pipe at the manifold.
  10.  
  11. Lower the vehicle.
  12.  
  13. Detach the electrical connector from the oxygen sensor.
  14.  
  15. Remove the rear timing belt tensioner actuator using the following procedure
    1. Remove the timing belt tensioner actuator pulley.
    2.  
    3. Remove the timing belt tensioner mounting bracket bolts. Do this by aligning the tool to the socket in the bolt head.
    4.  
    5. Remove the timing belt tensioner mounting bracket. Use care as there is a mounting base gasket. Reattach the gasket to the mounting bracket is the gasket is loose.
    6.  

  16.  
  17. Remove the cylinder head bolts and carefully lift the head along with the exhaust manifold from the vehicle. Discard the gasket.
  18.  

To install:


NOTE
The cylinder head should be cleaned and inspected before installation. Please see the Engine Reconditioning section.

  1. Clean all parts well. Use care when working with light alloy parts not to gouge or scratch the gasket sealing surfaces. Clean the head bolts well. New replacement bolts are recommended. Clean the cylinder block bolt threads. Make sure all of the oil is removed from the bolt holes.
  2.  
  3. Carefully lay a new gasket on the engine block deck. Some brands of gaskets may say TOP or have some other marking indicating the surface that should face the cylinder head. Make sure the gasket sits flat on the block deck.
  4.  
  5. Carefully install the cylinder head to the block. Align any dowel pins or other locators. Install the head bolts and finger-tighten. Tighten gradually and in sequence, working up to 44 ft. lbs. (60 Nm). After achieving final torque, use a torque angle meter to turn the bolts an additional 90 degrees ( 1 / 4 turn).
  6.  
  7. Install the timing belt tensioner making sure the gasket is in place. Tighten the bolts to 37 ft. lbs. (50 Nm). Install the timing belt tensioner pulley.
  8.  
  9. Connect the oxygen sensor wire.
  10.  
  11. Raise and safely support the vehicle.
  12.  
  13. Install the front exhaust pipe to the rear manifold. Lower the vehicle.
  14.  
  15. Install the exhaust crossover pipe.
  16.  
  17. Install the right camshaft carrier using the following procedure.
    1. Make sure that the pieces of rubber tubing are in place under the camshaft and in between the lifter to hold the lifters in carrier.
    2.  
    3. Remove the oil from the camshaft carrier-to-cylinder head bolts.
    4.  
    5. Install a new camshaft carrier gasket.
    6.  

  18.  


WARNING
Remove the oil from the camshaft hold-down tool hole in the carrier before installing and tightening the bolt.

  1. Install J 38613-A or equivalent camshaft hold-down tool. Tighten the bolt to 22 ft. lbs. (30 Nm).
  2.  


NOTE
The use of petroleum jelly (never chassis grease) in the lifter bores, along with the use of the lifter hold-down hoses mentioned above, will help keep the lifters in place.

  1. Install the camshaft carrier to the cylinder head and position the hold-down bolts.
  2.  
  3. Tighten the camshaft carrier bolts to 20 ft. lbs. (27 Nm).
  4.  
  5. Remove the lifter hold-down hoses.
  6.  

  1. Install the lower and upper intake manifold following the procedures given in this section.
  2.  
  3. Install the remaining components in the reverse order of the removal process. Since coolant will run down into the engine oil system when the head is removed, it is most important to drain the engine oil and refill with clean engine oil. A filter change is also recommended.
  4.  

3.5L Engine
Left (Front)

WARNING
As with many procedures on the 3.5L (VIN H) DOHC engine, cylinder head removal is a long and complicated task. Be very sure of your diagnosis before attempting to remove the heads on this engine, especially with the engine still in the vehicle. A compression test and/or leakdown test should be performed. A pair of special tools, GM #J 42042 Camshaft Timing Clamps, is required to hold the camshafts in place once the timing chain is removed and the head bolts loosened. This tool, when properly installed, will be fully seated on the camshaft ends with the camshaft flats parallel to the cam cover sealing surfaces. This tool prevents unexpected camshaft rotation caused by valve spring pressure. This tool must be installed immediately after cam cover removal. Remember, the valve timing must be reset if the camshaft drive sprockets are removed from their camshafts. Once lost, there are no pins or keys to help you re-establish valve timing. In addition, GM specifies that new service replacement head bolts must be used. Do not reuse the head bolts. Procure the necessary parts before beginning this procedure.


NOTE
This engine is constructed primarily of aluminum. Use care when working with light alloy parts.

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the coolant and the engine oil into suitable containers.
  4.  
  5. Remove the upper and lower intake manifolds using the procedures found in this section.
  6.  
  7. Remove the water outlet housing (thermostat housing). Adjust the water crossover pipe for access.
  8.  
  9. Remove the engine mount strut bracket.
  10.  
  11. Remove the left side (front) exhaust manifold using the procedures found in this section.
  12.  
  13. Remove both camshaft covers using the procedures found in this section.
  14.  
  15. Install special tool J 42038, or equivalent on the camshafts. There should be two flat portions on the camshafts. The tool fits down on these flats to keep valve spring pressure from rotating the camshafts. Proceed no further if you do not have this tool or its functional equivalent.
  16.  
  17. Remove the primary camshaft drive chain using the procedures found in this section.
  18.  
  19. Remove the left side (front) cylinder head camshafts using the procedures found in this section.
  20.  


NOTE
Place the valve train parts in a rack in the order in which they are being removed so that they can be installed in the same location from which they were removed.

  1. Remove the valve rocker arms and lifters.
  2.  


NOTE
The head bolts are different sizes. While the head bolts must not be reused, it is good practice to note the location of each removed bolt so its correct replacement can be installed. Some technicians will place a replacement head gasket on a clean piece of cardboard and trace out the head bolt holes. The head bolts are punched through the cardboard in their corresponding locations as they are removed. In this way, the replacement bolts can be compared to the originals and the new replacement bolts eventually installed in their correct locations.

  1. Remove the head bolts observing the following:
    1. Remove the M6 external drive bolts from the front portion of the cylinder head. Note the location of the longer M6 bolt.
    2.  
    3. Remove and discard the M11 internal drive head bolts. DO NOT reuse the cylinder head bolts.
    4.  

  2.  
  3. Remove the cylinder head. Make sure the locating dowel guide pins are not pulled from the engine block and stuck in the head. Place the head on a flat, clean surface with the combustion chambers face-up to prevent damage to the deck face. Discard the gasket.
  4.  



Click image to see an enlarged view

Fig. Left side (front) cylinder head, gasket and bolt torque sequence-3.5L (VIN H) engine

To install:


NOTE
The cylinder head should be cleaned and inspected before installation. Please see the Engine Reconditioning section.

  1. Clean all parts well. The heads are aluminum. Use care not to gouge or scratch the gasket sealing surfaces. It is good practice to clean the head bolt threaded holes in the engine block. This cleans out old sealer, rust and other debris which could interfere with getting an accurate torque reading. Use the correct size thread cutting tap, but use care since the engine block is also aluminum. Make sure all of the oil is removed from the bolt holes.
  2.  


WARNING
This engine uses special torque to yield head bolts. This design bolt requires a special tightening procedure. Failure to follow the given procedure will cause head gasket failure and possible engine damage. The head bolts used on this engine are designed to permanently stretch when tightened. The correct part number fastener must be used to replace this type of fastener. Do not use a bolt which is stronger in this application. If the correct bolt is not used, the parts will not be tightened correctly. The components may be damaged. In addition, the factory specifies new service replacement head bolts of the correct part number be used.

  1. Carefully lay a new head gasket on the engine block deck. Verify that the arrow or whatever marking is used on the gasket indicating which side is up and/or forward, is correctly aligned. Make sure the gasket sits flat on the block deck, not hung up on the alignment dowels. The alignment dowels (locating pins) should hold the gasket in place. Check that all the bolt holes and water passages line up correctly. Use no sealer on head gaskets.
  2.  


WARNING
A torque angle meter must be used to tighten these head bolts.

  1. Carefully install the cylinder head to the block. Align the dowel pins. Install the new head bolts and finger-tighten. The M11 bolts MUST NOT be reused. Tighten gradually, in the proper sequence, in the following steps.
    1. Using a torque angle meter, tighten the M11 bolts in sequence to 22 ft. lbs. (30 Nm) plus 60 degrees.
    2.  
    3. Repeat the sequence turning each bolt an additional 60 degrees.
    4.  
    5. Repeat the sequence again, turning each bolt an additional 60 degrees (total 180 degrees).
    6.  
    7. Tighten the long M6 bolt to 22 ft. lbs. (30 Nm).
    8.  
    9. Tighten the two short M6 bolts to 106 inch lbs. (12 Nm).
    10.  

  2.  
  3. Install the lifters and the rocker arms.
  4.  
  5. Install the camshafts using the procedures found in this section.
  6.  
  7. Install the primary camshaft drive using the procedures found in this section.
  8.  
  9. Remove tool J 42038, or equivalent, from the camshafts.
  10.  
  11. Install the camshaft covers.
  12.  
  13. Install the remaining components in the reverse order of the removal process. Since coolant will run down into the engine oil system when the head is removed, it is most important to drain the engine oil and refill with clean engine oil. A filter change is also recommended.
  14.  

Right (Rear)

WARNING
As with many procedures on the 3.5L (VIN H) DOHC engine, cylinder head removal is a long and complicated task. Be very sure of your diagnosis before attempting to remove the heads on this engine, especially with the engine still in the vehicle. A compression test and/or leakdown test should be performed. A pair of special tools, GM #J 42042 Camshaft Timing Clamps, is required to hold the camshafts in place once the timing chain is removed and the head bolts loosened. This tool, when properly installed, will be fully seated on the camshaft ends with the camshaft flats parallel to the cam cover sealing surfaces. This tool prevents unexpected camshaft rotation caused by valve spring pressure. This tool must be installed immediately after cam cover removal. Remember, the valve timing must be reset if the camshaft drive sprockets are removed from their camshafts. Once lost, there are no pins or keys to help you re-establish valve timing. In addition, GM specifies that new service replacement head bolts must be used. Do not reuse the head bolts. Procure the necessary parts before beginning this procedure.


NOTE
This engine is constructed primarily of aluminum. Use care when working with light alloy parts.

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the coolant and the engine oil.
  4.  
  5. Remove the upper and lower intake manifolds using the procedures found in this section.
  6.  


WARNING
DO NOT remove the right side (rear) exhaust manifold from the cylinder head.

  1. Remove the water outlet housing (thermostat housing). Adjust the water crossover pipe for access.
  2.  
  3. Remove both camshaft covers using the procedures found in this section.
  4.  
  5. Install tool J 42038 on the camshafts. There should be two flat portions on the camshafts. The tool fits down on these flats to keep valve spring pressure from rotating the camshafts. Proceed no further if you do not have this tool or its functional equivalent.
  6.  
  7. Remove the primary camshaft drive chain using the procedures found in this section.
  8.  
  9. Remove the right side (rear) cylinder head camshafts using the procedures found in this section.
  10.  


NOTE
Place the valve train parts in a rack in the order in which they are being removed that that they can be installed in the same location from which they were removed.

  1. Remove the valve rocker arms and lifters.
  2.  
  3. Remove the coolant temperature sensor from the right side (rear) cylinder head.
  4.  


NOTE
The head bolts are different sizes. While the head bolts must not be reused, it is good practice to note the location of each removed bolt so its correct replacement can be installed. Some technicians will place a replacement head gasket on a clean piece of cardboard and trace out the head bolt holes. The head bolts are punched through the cardboard in their corresponding locations as they are removed. In this way, the replacement bolts can be compared to the originals and the new replacement bolts eventually installed in their correct locations.

  1. Remove the head bolts observing the following.
    1. Remove the M6 external drive bolts from the front portion of the cylinder head. Note the location of the longer M6 bolt.
    2.  
    3. Remove and discard the M11 internal drive head bolts. DO NOT reuse the cylinder head bolts.
    4.  

  2.  
  3. Remove the cylinder head. Make sure the locating dowel guide pins are not pulled from the engine block and stuck in the head. Place the head on a flat, clean surface with the combustion chambers face-up to prevent damage to the deck face. Discard the gasket.
  4.  



Click image to see an enlarged view

Fig. Right side (rear) cylinder head, gasket and bolt torque sequence-3.5L (VIN H) engine

To install:


NOTE
The cylinder head should be cleaned and inspected before installation. Please see the Engine Reconditioning section.

  1. Clean all parts well. The heads are aluminum. Use care not to gouge or scratch the gasket sealing surfaces. It is good practice to clean the head bolt threaded holes in the engine block. This cleans out old sealer, rust and other debris which could interfere with getting an accurate torque reading. Use the correct size thread cutting tap, but use care since the engine block is also aluminum. Make sure all of the oil is removed from the bolt holes.
  2.  


WARNING
This engine uses special torque to yield head bolts. This design bolt requires a special tightening procedure. Failure to follow the given procedure will cause head gasket failure and possible engine damage. The head bolts used on this engine are designed to permanently stretch when tightened. The correct part number fastener must be used to replace this type of fastener. Do not use a bolt which is stronger in this application. If the correct bolt is not used, the parts will not be tightened correctly. The components may be damaged. In addition, the factory specifies new service replacement head bolts of the correct part number be used.

  1. Carefully lay a new head gasket on the engine block deck. Verify that the arrow or whatever marking is used on the gasket indicating which side is up and/or forward, is correctly aligned. Make sure the gasket sits flat on the block deck, not hung up on the alignment dowels. The alignment dowels (locating pins) should hold the gasket in place. Check that all the bolt holes and water passages line up correctly. Use no sealer on head gaskets.
  2.  


WARNING
A torque angle meter must be used to tighten these head bolts.

  1. Carefully install the cylinder head to the block. Align the dowel pins. Install the new head bolts and finger-tighten. The M11 bolts MUST NOT be reused. Tighten gradually and in the following sequence.
    1. Using a torque angle meter, tighten the M11 bolts in sequence to 22 ft. lbs. (30 Nm) plus 60 degrees.
    2.  
    3. Repeat the sequence turning each bolt an additional 60 degrees.
    4.  
    5. Repeat the sequence again, turning each bolt an additional 60 degrees (total 180 degrees).
    6.  
    7. Tighten the long M6 bolt to 22 ft. lbs. (30 Nm).
    8.  
    9. Tighten the two short M6 bolts to 106 inch lbs. (12 Nm).
    10.  

  2.  
  3. Install the coolant temperature sensor into the cylinder head.
  4.  
  5. Install the lifters and rocker arms using the procedures found in this section.
  6.  
  7. Install the right side (rear) camshaft using the procedures found in this section.
  8.  
  9. Install the primary camshaft drive using the procedures found in this section.
  10.  
  11. Remove tool J 42038, or equivalent, from the camshafts.
  12.  
  13. Install the camshaft covers.
  14.  
  15. Install the remaining components in the reverse order of the removal process. Since coolant will run down into the engine oil system when the head is removed, it is most important to drain the engine oil and refill with clean engine oil. A filter change is also recommended.
  16.  

3.8L Engine
Left Side (Front)
  1. Disconnect the negative battery cable.
  2.  
  3. Drain the coolant and the engine oil into suitable containers.
  4.  
  5. Remove the cosmetic/acoustic engine cover.
  6.  
  7. Remove the air cleaner duct.
  8.  
  9. Remove the right engine mount strut.
  10.  
  11. Remove the upper and lower intake manifolds, using the procedures found in this section.
  12.  
  13. Remove the left side (front) rocker arms and pushrods.
  14.  
  15. Remove the cylinder head bolts and lift the cylinder head from the engine. Discard the gasket.
  16.  



Click image to see an enlarged view

Fig. Cylinder head and gasket arrangement and bolt tightening sequence-3.8L engines

To install:


NOTE
The cylinder head should be cleaned and inspected before installation. Please see the Engine Reconditioning section.

  1. Clean all parts well. Use care not to gouge or scratch the gasket sealing surfaces. It is good practice to clean the head bolt threaded holes in the engine block. This cleans out old sealer, rust and other debris which could interfere with getting an accurate torque reading. Use the correct size thread cutting tap. Most 3.8L engines will require a 7/16-14 tap. Make sure all of the oil is removed from the bolt holes.
  2.  


WARNING
This engine uses special torque to yield head bolts. This design bolt requires a special tightening procedure. Failure to follow the given procedure will cause head gasket failure and possible engine damage. The head bolts used on this engine are designed to permanently stretch when tightened. The correct part number fastener must be used to replace this type of fastener. Do not use a bolt which is stronger in this application. If the correct bolt is not used, the parts will not be tightened correctly. The components may be damaged. In addition, the factory recommends new service replacement head bolts of the correct part number be used.


NOTE
The head gaskets on the 3.8L engine are not interchangeable. The head gasket must be installed with the arrow (or noting any other mark, depending on the gasket manufacturer) pointing to the front of the engine. Installing the gasket in any other direction will cause gasket failure and possible engine failure.

  1. Carefully lay a new head gasket on the engine block deck. Verify that the arrow or whatever marking is used on the gasket indicating which side is up and/or forward, is correctly aligned. Make sure the gasket sits flat on the block deck, not hung up on the alignment dowels. Check that all the bolt holes and water passages line up correctly. Use no sealer on head gaskets.
  2.  
  3. Carefully install the cylinder head to the block. Align any dowel pins or other locators. Install the head bolts and finger-tighten. Tighten gradually in the following sequence:
    1. Tighten the bolts in sequence to 37 ft. lbs. (50 Nm).
    2.  
    3. Using a torque angle meter, rotate each bolt an additional 130 degrees, in sequence.
    4.  
    5. Rotate the center four bolts an additional 30 degrees, in sequence.
    6.  

  4.  
  5. Install the pushrods and rocker arms using the procedures found in this section.
  6.  
  7. Install the lower and upper intake manifold following the procedures given in this section.
  8.  
  9. Install the remaining components in the reverse order of the removal process. Since coolant will run down into the engine oil system when the head is removed, it is most important to drain the engine oil and refill with clean engine oil. A filter change is recommended.
  10.  

Right Side (Rear)
  1. Disconnect the negative battery cable.
  2.  
  3. Drain the coolant and the engine oil into suitable containers.
  4.  
  5. Remove the cosmetic/acoustic engine cover.
  6.  
  7. Remove the air cleaner duct.
  8.  
  9. Remove the accessory drive belt tensioner.
  10.  
  11. Remove the EGR valve.
  12.  
  13. Remove the upper and lower intake manifold using the procedures found in this section.
  14.  
  15. Remove the right side (rear) exhaust manifold using the procedures found in this section.
  16.  
  17. Remove the right side (rear) rocker arms and pushrods.
  18.  
  19. Remove the cylinder head bolts and lift the cylinder head from the engine. Discard the gasket.
  20.  

To install:


NOTE
The cylinder head should be cleaned and inspected before installation. Please see the Engine Reconditioning section.

  1. Clean all parts well. Use care not to gouge or scratch the gasket sealing surfaces. It is good practice to clean the head bolt threaded holes in the engine block. This cleans out old sealer, rust and other debris which could interfere with getting an accurate torque reading. Use the correct size thread cutting tap. Most 3.8L engines will require a 7/16-14 tap. Make sure all of the oil is removed from the bolt holes.
  2.  


WARNING
This engine uses special torque to yield head bolts. This design bolt requires a special tightening procedure. Failure to follow the given procedure will cause head gasket failure and possible engine damage. The head bolts used on this engine are designed to permanently stretch when tightened. The correct part number fastener must be used to replace this type of fastener. Do not use a bolt which is stronger in this application. If the correct bolt is not used, the parts will not be tightened correctly. The components may be damaged. In addition, the factory recommends new service replacement head bolts of the correct part number be used.


NOTE
The head gaskets on the 3.8L engine are not interchangeable. The head gasket must be installed with the arrow (or noting any other mark, depending on the gasket manufacturer) pointing to the front of the engine. Installing the gasket in any other direction will cause gasket failure and possible engine failure.

  1. Carefully lay a new head gasket on the engine block deck. Verify that the arrow or whatever marking is used on the gasket indicating which side is up and/or forward, is correctly aligned. Make sure the gasket sits flat on the block deck, not hung up on the alignment dowels. Check that all the bolt holes and water passages line up correctly. Use no sealer on head gaskets.
  2.  
  3. Carefully install the cylinder head to the block. Align any dowel pins or other locators. Install the head bolts and finger-tighten. Tighten gradually and in the following sequence:
    1. Tighten the bolts in sequence to 37 ft. lbs. (50 Nm).
    2.  
    3. Using a torque angle meter, rotate each bolt an additional 130 degrees, in sequence.
    4.  
    5. Rotate the center four bolts an additional 30 degrees, in sequence.
    6.  

  4.  
  5. Install the pushrods and rocker arms using the procedures found in this section.
  6.  
  7. Install the lower and upper intake manifold using the procedures found in this section.
  8.  
  9. Install the remaining components in the reverse order of the removal process. Since coolant will run down into the engine oil system when the head is removed, it is most important to drain the engine oil and refill with clean engine oil. A filter change is also strongly recommended.
  10.  

 
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