Hydraulic Lash Adjuster Valve Lifters - Lifter Troubleshooting

GENERAL INFORMATION.

1) Temporary increased valve noise immediately after engine start-up is

normal. This noise occurs because oil has leaked out of those lifters that were loaded by the valve springs of open valves while the engine was off. Several seconds are required after engine start for the

hydraulic lash adjusters to begin functioning normally.

2) Intermittent noise at engine idle that stops as engine speed increases,

may indicate a defect in the check ball valve surface or contamination of the hydraulic lash adjuster mechanism.

Remedy.

PROCEDURE.

1. Clean and inspect the lifter components.

2. Replace the worn check ball.

3) Increased noise at low idle speed or on a fully warmed-up engine. Noise disappears on a cold engine or when engine speed increases.

The cause is excessive oil leakage through the clearance between the plunger and the lifter body. Replace the worn lifter.

4) Increased noise at high vehicle speeds, disappearing at

at low speeds, may be caused by the following reasons.

– oil level too high (above the MAX mark on the dipstick). Intensive

stirring and splashing of oil by the crankshaft leads to foam entering

the hydraulic lash adjusters of the tappets with an air-oil mixture. This causes

abnormal operation of the hydraulic lash adjusters.

– oil level too low (below the MIN mark on the dipstick). This causes the oil pump to draw in air and abnormal operation of the valve lash hydraulic lash adjusters.

Correction: add oil and bring the level to normal.

– oil pan bent, oil pick-up strainer raised or its mounting loosened. Replace or repair defective parts, tighten mounting bolts.

5) Increased noise at engine idle, increasing with crankshaft speed up to 1500 rpm. This noise is not related to the tappets. At low

idle speed the noise may disappear completely or appear as a light knock.

of one or more valves. Possible causes may be the following.

– severe wear of the valve tip or rocker arm.

– excessive clearance between valve stems and guides.

– excessive misalignment of valve and seat.

– non-parallel valve spring ends.

– excessive runout of the valve head face.

– contact of the valve spring damper with the valve rotator mechanism.

To check the spring condition and guide clearances, remove the valve cover.

Sometimes the noise can be eliminated by slightly turning the spring or valve.

Turn the crankshaft to the position where the suspect valve lifts.

off the seat. Turn the spring. The valve will turn at the same time. With this adjustment

achieve quiet valve operation. If turning the spring and valve does not

give results, check the spring condition. If the bend deformation of the spring in the

free state exceeds 1.6 mm, replace the spring.

Check the clearances between valve stems and guides. Eliminate increased clearances.

6) Constant noise, not dependent on crankshaft speed. Possible causes are increased valve lash in the valve train or foreign particles in the mechanism. Check valve lash by setting

the piston of the corresponding cylinder to TDC on the compression stroke. If there is clearance, the pushrod moves freely up and down between the cam

and the valve rocker arm. If the clearance is normal, clean the hydraulic lash adjuster.

tappet.