Hyundai Coupes/Sedans 1986-1993 Repair Guide

Hydraulic Lash Adjusters

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Hydraulic lash adjusters are used in the 4 and 6 cylinder engines on Sonata.

The hydraulic lash adjuster is a precision component that relies on a clean operating environment. When handling the lash adjuster, make certain that no dirt or foreign particles are allowed to get inside the unit. DO NOT try to take the unit apart as it is not rebuildable. The adjuster is filled with diesel fuel. Hold the adjuster in the upright position so that the diesel fuel does not spill out. When cleaning the unit, only use clean diesel fuel.

REMOVAL & INSTALLATION



See Figures 1, 2, 3 and 4



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Fig. Fig. 1: Lash adjuster holding tool installed-using the tool prevents the adjuster from coming out of the rocker arm



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Fig. Fig. 2: Bleeding the hydraulic lash adjusters



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Fig. Fig. 3: Lash adjuster leak-down test



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Fig. Fig. 4: Installing the lash adjuster-once the adjuster is installed, use the holding tool to keep it in position

1596cc, 1796cc and 1997cc Engines
  1. Release the fuel system pressure. Disconnect the negative battery cable.
  2.  
  3. Disconnect the accelerator cable, PCV hoses, breather hoses, spark plug cables and the remove the valve cover.
  4.  
  5. Rotate the crankshaft clockwise and align the timing marks so No. 1 piston will be at TDC of the compression stroke. At this time the timing marks on the camshaft sprocket and the upper surface of the cylinder head should coincide, and the dowel pin of the camshaft sprocket should be at the upper side.
  6.  

Always rotate the crankshaft in a clockwise direction. Make a mark on the back of the timing belt indicating the direction of rotation so it may be reassembled in the same direction if it is to be reused.

  1. Remove the timing belt upper and lower covers.
  2.  
  3. Remove the timing belt.
  4.  
  5. Remove the crank angle sensor.
  6.  
  7. Remove the camshafts.
  8.  
  9. Visually inspect the rocker arm roller and replace if dent, damage or seizure is evident. Check the roller for smooth rotation. Replace if excess play or binding is present. Also, inspect valve contact surface for possible damage or seizure. It is recommended that all rocker arms and lash adjusters be replaced together.
  10.  

To install:
  1. Install the lash adjusters and rocker arms into the cylinder head. Lubricate lightly with clean oil prior to installation.
  2.  
  3. Apply engine oil to the lobes and journals of each camshaft. Install the camshafts into the cylinder head taking care not to confuse the intake and the exhaust camshaft; the intake camshaft has a slit on its rear end for driving the crank angle sensor. Align shafts so dowel pins on camshaft sprocket end are located on the top.
  4.  
  5. Install and tighten the camshaft bearing caps in the proper sequence tightening to 14-15 ft. lbs. (19-21 Nm), in 3 even progressions.
  6.  
  7. Replace the camshaft oil seals and install the sprockets.
  8.  
  9. Locate the dowel pin on the sprocket end of the intake camshaft at the top position, if not already done.
  10.  
  11. Align the punch mark on the crank angle sensor housing with the notch on the sensor plate. Install the crank angle sensor into the cylinder head.
  12.  
  13. Install the timing belt, covers and related components.
  14.  
  15. Install the valve cover using a new gasket. Reconnect all related components.
  16.  
  17. Reconnect the negative battery cable.
  18.  

2351cc and 2972cc Engines
  1. Disconnect the negative battery cable. Remove the air cleaner assembly.
  2.  
  3. Remove the valve cover.
  4.  

The lash adjuster is incorporated in the rocker arm on the side of the valve spring. When removing the rocker arm, a special tool must be used the prevent the lash adjuster from falling out.

  1. Using the lash adjuster retainer tools MD998443 or equivalent, install them on the rocker arms.
  2.  
  3. On the right side cylinder head, remove the distributor extension.
  4.  
  5. Hold the rear end of the camshaft down. If the rear of the camshaft cannot be held down, the belt will dislodge and the valve timing will be lost. Loosen the camshaft cap bolts but do not remove them from the caps. Remove the caps, arms, shafts and bolts all as an assembly.
  6.  
  7. Remove the lash adjuster(s) from the rocker arm(s).
  8.  
  9. Lubricate the lash adjuster(s) and their bore(s) with clean engine oil.
  10.  
  11. The installation is the reverse of the removal procedure.
  12.  
  13. Connect the negative battery cable and check the lash adjusters for proper operation.
  14.  

BLEEDING HYDRAULIC LASH ADJUSTERS



Removed from the Engine

To bleed the hydraulic lash adjusters when disassembling the rocker arms or as part of an engine overhaul, perform the following:

  1. Mount the adjuster into special bleeding tool 09246-32100 and immerse the tool and adjuster in a container of clean diesel fuel.
  2.  
  3. With air bleed wire 09246-32200 inserted in the adjuster, lightly press down on the steel ball and compress the plunger four or five times.
  4.  
  5. Remove the air bleed wire from the adjuster and push down firmly on the plunger. If the plunger moves even slightly, repeat Steps 1 and 2 until the plunger stops moving. If the plunger continues to move, replace it.
  6.  

During Driving

If the lash adjuster is removed and the diesel fuel contained inside is spilled, submerge the adjuster in clean diesel fuel and compress it several times to expel the air using the procedure described above. If air is still trapped after assembly and installation, and a clattering noise is heard when the engine is started, the air can be bled by increasing engine speed from idle to 3000 rpm and back to idle over a one minute period. Do this several times, or until the clattering stops. If this does not stop the clattering, remove and submerge the lifter in clean diesel fuel, compressing it several times as described above. If clattering continues, replace the lash adjuster.

 
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