Lash Adjuster Check

If an abnormal noise (clattering noise) suspected to be caused by malfunction of the lash adjuster is produced immediately after starting the engine and does not disappear, perform the following check.

NOTES
^ An abnormal noise due to malfunction of the lash adjuster is produced immediately after starting the engine and changes with the engine speed, regardless of the engine load. If the abnormal noise is not produced immediately after Starting the engine, or does not change with the engine speed, or it changes with the engine load, malfunction of the lash adjuster is not the cause for the abnormal noise.

^ When the lash adjuster is malfunctioning, the abnormal noise is rarely eliminated by continuing the warming-up of the engine at idle speed. However, the abnormal noise may disappear only when seizure is caused by oil sludge in the engine if the oil is not maintained properly.

1. Start the engine.

2. Check if abnormal noise produced immediately after starting the engine changes with the change in the engine speed. If the abnormal noise is not produced immediately after starting the engine or it does not change with the engine speed, malfunction of the lash adjuster is not the cause for the noise. Therefore, investigate other causes. If the abnormal noise does not change with the engine speed, it is probably caused by some parts other than the engine. (In this case, the valve lash adjuster is in good condition.)

3. With the engine idling, change the engine load (shift from N to D range, for example) to make sure that there is no change in the level of abnormal noise. If there is a change in the level of abnormal noise, a tapping noise due to worn crankshaft bearing or connecting rod bearing is suspected. (In this case, the lash adjuster is in good condition.)

4. After the engine is warmed up, run it at idle and check for abnormal noise. If the noise is reduced or disappears, check for a seizured lash adjuster. If there is no change in the level of the abnormal noise, proceed to Step 5.

a. Allow the engine to cool sufficiently.

b. Rotate the crankshaft two complete rotations.

c. Perform the Simple Lash Adjuster Check.

^ Replace the lash adjuster if the rocker arm can be pushed down easily.

^ If the lash adjuster is found normal as a result of simple lash adjuster check (the rocker arm is not pushed down easily), investigate other causes for the abnormal noise.

CAUTION
Before installing a new valve lash adjuster, be sure to bleed air from the adjuster.

5. Run the engine to bleed the lash adjuster system.

6. If the abnormal noise does not disappear after air bleeding operation, perform the Simple Lash Adjuster Check.

^ If only one of the lash adjusters is found abnormal (the rocker arm is pushed down easily), replace the lash adjuster.

^ If two or more lash adjusters are found abnormal (the rocker arm is pushed down easily), clogged oil passage in the cylinder head is suspected. Check for clogged oil passage and repair the passage if it is clogged. If the passage is not clogged, replace the adjusters.

^ If all the lash adjusters are found normal (the rocker arms are hard to push down), investigate other possible causes for the abnormal noise.

CAUTION
Before installing a new valve lash adjuster, be sure to bleed air from the adjuster.

7. Start the engine and make sure that the abnormal noise has disappeared. Perform air bleeding operation if required.

8. On DOHC engine, the lash adjuster can be replaced by the following procedure:

CAUTION
Before removing the lash adjuster, turn the crankshaft to lower the piston of the cylinder concerned. Otherwise, the valve will contact the piston when the valve is lowered. Also, the lash adjuster cannot be removed if the cam is holding the valve open.





In this case, turn the crankshaft so that the rocker arm may not be lifted by the cam.

a. Use the special tool to push down the valve down and remove the roller rocker arm.

b. Pull out the lash adjuster from the cylinder head.

c. Install the new lash adjuster. Be sure the air has been bled from the adjuster.

d. Use the special tool to push the valve down and install the roller rocker arm.

NOTE
To install the roller rocker arm, place the pivot end of the rocker arm on the lash adjuster first. Then push the valve down and place the machined end of the rocker arm on the valve stem end.