Engine Overhaul Tips
Aluminum has become extremely popular for use in engines, due to its low weight. Observe the following precautions when handling aluminum parts:
When assembling the engine, any parts that will be exposed to frictional contact must be prelubed to provide lubrication at initial start-up. Any product specifically formulated for this purpose can be used, but engine oil is not recommended as a prelube in most cases.
When semi-permanent (locked, but removable) installation of bolts or nuts is desired, threads should be cleaned and coated with Loctite® or another similar, commercial non-hardening sealant.
Most engine overhaul procedures are fairly standard. In addition to specific parts replacement procedures and specifications for your individual engine, this section is also a guide to acceptable rebuilding procedures. Examples of standard rebuilding practice are given and should be used along with specific details concerning your particular engine.
Competent and accurate machine shop services will ensure maximum performance, reliability and engine life. In most instances it is more profitable for the do-it-yourself mechanic to remove, clean and inspect the component, buy the necessary parts and deliver these to a shop for actual machine work.
Much of the assembly work (crankshaft, bearings, piston rods, and other components) is well within the scope of the do-it-yourself mechanic's tools and abilities. You will have to decide for yourself the depth of involvement you desire in an engine repair or rebuild.Repairing Damaged Threads
Several methods of repairing damaged threads are available. Heli-Coil® (shown here), Keenserts® and Microdot® are among the most widely used. All involve basically the same principle-drilling out stripped threads, tapping the hole and installing a prewound insert-making welding, plugging and oversize fasteners unnecessary.
Two types of thread repair inserts are usually supplied: a standard type for most inch coarse, inch fine, metric course and metric fine thread sizes and a spark lug type to fit most spark plug port sizes. Consult the individual tool manufacturer's catalog to determine exact applications. Typical thread repair kits will contain a selection of prewound threaded inserts, a tap (corresponding to the outside diameter threads of the insert) and an installation tool. Spark plug inserts usually differ because they require a tap equipped with pilot threads and a combined reamer/tap section. Most manufacturers also supply blister-packed thread repair inserts separately in addition to a master kit containing a variety of taps and inserts plus installation tools.
Before attempting to repair a threaded hole, remove any snapped, broken or damaged bolts or studs. Penetrating oil can be used to free frozen threads. The offending item can usually be removed with locking pliers or using a screw/stud extractor. After the hole is clear, the thread can be repaired, as shown in the series of accompanying illustrations and in the kit manufacturer's instructions.Tools
The tools required for an engine overhaul or parts replacement will depend on the depth of your involvement. With a few exceptions, they will be the tools found in a mechanic's tool kit (see Section 1 of this manual). More in-depth work will require some or all of the following:
The use of most of these tools is illustrated in this section. Many can be rented for a one-time use from a local parts jobber or tool supply house specializing in automotive work.
Occasionally, the use of special tools is called for. See the information on Special Tools and the Safety Notice in the front of this book before substituting another tool.Engine Preparation
To properly rebuild an engine, you must first remove it from the vehicle, then disassemble and diagnose it. Ideally you should place your engine on an engine stand. This affords you the best access to the engine components. Follow the manufacturer-s directions for using the stand with your particular engine. Remove the flywheel before installing the engine to the stand.
Now that you have the engine on a stand, and assuming that you have drained the oil and coolant from the engine, it-s time to strip it of all but the necessary components. Before you start disassembling the engine, you may want to take a moment to draw some pictures, or fabricate some labels or containers to mark the locations of various components and the bolts and/or studs which fasten them. Modern day engines use a lot of little brackets and clips which hold wiring harnesses and such, and these holders are often mounted on studs and/or bolts that can be easily mixed up. The manufacturer spent a lot of time and money designing your vehicle, and they wouldn-t have wasted any of it by haphazardly placing brackets, clips or fasteners on the vehicle. If it-s present when you disassemble it, put it back when you assemble, you will regret not remembering that little bracket which holds a wire harness out of the path of a rotating part.
You should begin by unbolting any accessories still attached to the engine, such as the water pump, power steering pump, alternator, etc. Then, unfasten any manifolds (intake or exhaust) which were not removed during the engine removal procedure. Finally, remove any covers remaining on the engine such as the rocker arm, front or timing cover and oil pan. Some front covers may require the vibration damper and/or crank pulley to be removed beforehand. The idea is to reduce the engine to the bare necessities (cylinder head(s), valve train, engine block, crankshaft, pistons and connecting rods), plus any other -in block- components such as oil pumps, balance shafts and auxiliary shafts.
Finally, remove the cylinder heads from the engine block and carefully place on a bench. Disassembly instructions for each component follow later in this section.Engine Start-Up And Break-In
Breaking It In
Make the first miles on the new engine, easy ones. Vary the speed but do not accelerate hard. Most importantly, do not lug the engine, and avoid sustained high speeds until at least 100 miles. Check the engine oil and coolant levels frequently. Expect the engine to use a little oil until the rings seat. Change the oil and filter at 500 miles, 1500 miles, then every 3000 miles past that.Starting The Engine
Now that the engine is installed and every wire and hose is properly connected, go back and double check that all coolant and vacuum hoses are connected. Check that your oil drain plug is installed and properly tightened. If not already done, install a new oil filter onto the engine. Fill the crankcase with the proper amount and grade of engine oil. Fill the cooling system with a 50/50 mixture of coolant/water.
- Connect the vehicle battery.
Start the engine. Keep your eye on your oil pressure indicator; if it does not indicate oil pressure within 10 seconds of starting, turn the vehicle off.
WARNINGDamage to the engine can result if it is allowed to run with no oil pressure. Check the engine oil level to make sure that it is full. Check for any leaks and if found, repair the leaks before continuing. If there is still no indication of oil pressure, you may need to prime the system.
- Confirm that there are no fluid leaks (oil or other).
- Allow the engine to reach normal operating temperature (the upper radiator hose will be hot to the touch).
- At this point you can perform any necessary checks or adjustments, such as checking the ignition timing.
- Install any remaining components or body panels which were removed.
Now that you have just gone through all of that hard work, keep yourself from doing it all over again by thoroughly maintaining it. Not that you may not have maintained it before, heck you could have had one to two hundred thousand miles on it before doing this. However, you may have bought the vehicle used, and the previous owner did not keep up on maintenance, which is why you just went through all of that hard work. See-
Removal & Installation
- Before servicing the vehicle, refer to the Precautions section.
- Properly relieve the fuel system pressure.
- Drain the coolant and crankcase.
Remove or disconnect the following:
Negative battery cable
Recover the refrigerant from the A/C system
A/C compressor manifold
Support the engine using a suitable lift.
Left hand engine mount bolts
- Lower the engine and transaxle assembly and remove it from the vehicle.
Installation is the reverse of removal. Refer to the accompanying engine mounting illustration for all necessary torque specifications.
In the process of removing the engine, you will come across a number of steps which call for the removal of a separate component or system, such as -disconnect the exhaust system'' or -remove the radiator-. In most instances, a detailed removal procedure can be found elsewhere in this manual.
It is virtually impossible to list each individual wire and hose which must be disconnected, simply because so many different model and engine combinations have been manufactured. Careful observation and common sense are the best possible approaches to any repair procedure.
Removal and installation of the engine can be made easier if you follow these basic points:
The engine is removed with the transaxle attached. The engine and transaxle are lowered from the vehicle as an assembly.
- Properly relieve the fuel system pressure. Please refer to Fuel System, Electronic Fuel Injection, Relieving Fuel System Pressure for the procedure.
Disconnect the negative battery cable.
CAUTIONNever open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.
- Drain and recycle the engine coolant.
Remove the air cleaner assembly and air cleaner-to-intake manifold hose.
CAUTIONThe EPA warns that prolonged contact with used engine oil may cause a number of skin disorders, including cancer! You should make every effort to minimize your exposure to used engine oil. Protective gloves should be worn when changing the oil. Wash your hands and any other exposed skin areas as soon as possible after exposure to used engine oil. Soap and water, or waterless hand cleaner should be used.
- Drain the engine oil.
- On 1993-98 3.0L engines, disconnect the radiator overflow hose from the radiator filler neck and remove the recovery tank.
Label and disconnect all electrical connectors from the engine and transaxle.
CAUTIONObserve all applicable safety precautions when working around fuel. Whenever servicing the fuel system, always work in a well ventilated area. Do not allow fuel spray or vapors to come in contact with a spark or open flame. Keep a dry chemical fire extinguisher near the work area. Always keep fuel in a container specifically designed for fuel storage; also, always properly seal fuel containers to avoid the possibility of fire or explosion.
- Disconnect and plug the fuel lines.
- Disconnect the vacuum hoses from the evaporative emission (EVAP) canister. On 1993-98 California emissions vehicles and all 1999-00 vehicles, disconnect the Manifold Absolute Pressure (MAP) sensor electrical and vacuum connections. Next to the MAP sensor, disconnect the EVAP canister purge test port connections.
On 1993-98 3.0L engines:
Remove the ignition coil.
On 1999-00 3.3L engines:
Disconnect the distributor wiring harnesses.
- Disconnect the accelerator cable from the throttle lever. If the vehicle is equipped with cruise control, disconnect the actuator cable from the throttle lever.
- Remove the cable bracket from the upper intake manifold (plenum).
- Remove the upper and lower radiator hoses.
- Remove the A/C drive belt.
- Remove the two upper A/C compressor bolts.
- Disconnect the heater hoses.
- Disconnect the brake booster hose from the intake manifold.
- Remove the ground cable from the oil filler tube.
- Raise and safely support the vehicle.
- Remove the front wheels.
- Remove the inner and outer engine and transaxle splash shields.
- Remove the transaxle shift cable nut and shift cable from the manual shift linkage rod.
- Using a screwdriver, release the shift cable locking pin from the shift cable bracket and remove the cable from the bracket.
- At the front of the engine, remove the oil pressure sensor wire and the alternator electrical connections. Remove the alternator wiring bracket screw.
- Remove the accessory drive belts.
- Remove the power steering pump. Access the front power steering pump-to-bracket bolts by inserting a socket through the pulley holes.
- Remove the two lower A/C compressor bolts and position the compressor aside without disconnecting the refrigerant lines.
- Remove the exhaust inlet pipe.
- Remove the halfshafts. Please refer to Drive Train, Automatic Transaxle, Halfshafts, Removal and Installation for the procedure.
- Label and disconnect the transaxle cooler lines from the transaxle.
- Disconnect the transaxle ground connection.
- Position a suitable jack or powertrain lift under the engine and transaxle assembly. If necessary, place blocks of wood between the lift and the engine/transaxle assembly to prevent damage to the assembly or underbody components.
- Remove the front transaxle mount bolts.
- Remove the rear transaxle mount nuts.
- On 1993-98 3.0L engines, remove the two rear refrigerant/heater pipe hold-down bracket bolts.
- Remove the four transverse member bolts.
- Remove the transverse member-to-engine mount bolts and remove the transverse member.
- Carefully lower the engine and transaxle assembly from the vehicle.
Remove the crank position (CKP) sensor heat shield, the sensor, and the starter motor.
NOTEBe careful not to damage the crankshaft position sensor or the flywheel ring gear teeth during disassembly.
- Remove the bolts from both transaxle braces.
- Remove the lower transaxle-to-engine bolts.
- Remove the transaxle inspection cover.
- Mark the torque converter and flywheel to ensure proper positioning during reassembly.
- Remove the four torque converter-to-flywheel bolts. Use a socket on the crankshaft pulley bolt to rotate the flywheel and torque converter to gain access to the bolts, and to stop the crankshaft from turning.
- Remove the upper transaxle-to-engine bolts.
Separate the transaxle from the engine.
- The installation is the reverse of removal, but please note the following important steps.
- When assembling the transaxle to the engine, make sure that the alignment dowels are properly positioned. Tighten the lower transaxle-to-engine bolt to 22-30 ft. lbs. (30-40 Nm). Align the torque converter and flywheel to their original positions. Tighten the torque converter-to-flywheel bolts to 33-43 ft. lbs. (44-59 Nm). Tighten the upper transaxle-to-engine bolts to 29-36 ft. lbs. (39-49 Nm).
After raising the engine and transaxle assembly into the vehicle, tighten the transverse member bolts to 58-65 ft. lbs. (78-88 Nm).
WARNINGOperating the engine without the proper amount and type of engine oil will result in severe engine damage.
- Fill the cooling system. Fill the engine crankcase with the proper type of motor oil to the required level.
- Run the engine and check for leaks.