Examination
If a characteristic abnormal noise appears after starting the engine and does not disappear after the engine warms up, the hydraulic valve clearance compensators may be faulty and the following check should be performed.
Notes.
(1) Abnormal noise caused by a malfunction of the hydraulic valve clearance compensators appears immediately after starting the engine and changes with the engine speed, regardless of its load. If the abnormal noise does not appear immediately after starting the engine or does not change with engine speed, then the hydraulic valve clearance compensators are not the source of the noise.
(2) If the hydraulic valve clearance compensator is faulty, the abnormal noise rarely goes away when the engine warms up at idle. However, the abnormal noise may only disappear when the seizure is caused by engine oil contamination that is not properly maintained.
1. Start the engine.
2. Verify that the abnormal noise appears immediately after starting the engine and changes with the change in engine speed.
If the abnormal noise does not appear immediately after starting the engine or does not change with engine speed, then the hydraulic valve clearance compensators are working. Check the engine for other sources of noise. If the abnormal noise does not change with engine speed, it is likely caused by malfunctions of other engine components.
3. When the engine is idling, make sure that the noise level does not change with increasing engine load.
If the noise level fluctuates, the noise is likely caused by worn main or connecting rod bearing shells (In this case, the hydraulic valve clearance compensators are in good working order).
4. After warming up the engine to check for abnormal noise, leave it to idle.
If the noise decreases or disappears, clean the hydraulic valve clearance adjusters as they may be stuck. If the abnormal noise level has not changed, go to step 5.
5. Bleed the hydraulic valve lash adjusters.
6. If abnormal noise does not disappear after bleeding, clean the hydraulic valve clearance compensators.