Lifter / Lash Adjuster: Testing and Inspection

LASH ADJUSTERS CHECK

NOTE: Soon after the engine is started or while it is running. abnormal noise (clattering) which may be attributed to the adjuster sounds but does not stop. In this case, check the following.

(1) Check the engine oil. and refill or replace oil if necessary.

NOTE:
^ If the oil amount is small. air will be sucked from the oil strainer and mixed in the oil passage.
^ If the oil amount is excessive, the oil will be stirred by the crank and mixed with a large amount of air.
^ Air and oil can not be separated easily in the deteriorated oil. and the amount of air mixed in the oil increases.






If such mixed-in air enters the high pressure chamber in the lash adjuster, the air in the high-pressure chamber will be compressed while the valve is opened. the lash adjuster will be excessively compressed and abnormal noise will be produced when the valve is closed.

This is the same phenomenon which occurs when the valve clearance is improperly adjusted to be excessively large.

However, it will return to be normal if the air entrapped in the adjuster is released in this case.

(2) Start the engine, and slowly race* it several times (10 times or less).

If the abnormal noise is eliminated by racing the engine. it means that the air is released from the high-pressure chamber of the lash adjuster and the function of the lash adjuster is returned to normal.

Gradually increase the engine speed from the idle speed to 3.000 rpm (for 30 seconds). and then gradually slow down the engine to the idling speed (for 30 seconds).

NOTE:
^ If the vehicle is parked on a slope for a long time, the oil will be sometimes reduced in the lash adjuster. and air will enter the high-pressure chamber when the engine is started.
^ After the vehicle is parked for a long time, the oil will go Out of the oil passage. Since it takes a little time to supply oil to the lash adjuster, air sometimes enters the high-pressure chamber.






(3) If any abnormal noise is not eliminated by racing, check the lash adjuster.

(1) Stop the engine.
(2) Set the engine so that the No.1 cylinder is positioned at the top dead centre of the compression.
(3) Press the rocker arm at the area indicated by the arrow mark to check whether the rocker arm is lowered or not. Slowly turn the crankshaft 360 degrees clockwise.
(4) In the same procedure as Step 3, check the rocker arm at the area indicated by the arrow mark.






(5) If the rocker arm is lowered when it is pressed, replace the lash adjuster.
When the lash adjuster is replaced, bleed air from all adjusters and assemble them. Recheck them following Steps 1 to 5.
Moreover, if it is felt to be so hard that the rocker arm is not lowered when it is pressed. the lash adjuster is normal. Check for other causes of the abnormality.