Valve Lash Adjuster Noise Diagnosis

Valve Lash Adjuster Noise Diagnosis
In case of the following, valve lash adjuster noise may be caused by air trapped into valve lash adjusters.
^ Vehicle is left for 24 hours or more.
^ Engine oil is changed.
^ Hydraulic lash adjuster is replaced or reinstalled.
^ Engine is overhauled.

If noise from valve lash adjusters is suspected, perform the following checks.
1) Check engine oil for the following.
^ Oil level in oil pan
If oil level is low, add oil up to Full level hole on oil level gauge.
^ Oil quality
If oil is discolored, or deteriorated, change it. For particular oil to be used, refer to Engine Oil and Filter Change.
^ Oil leaks. If leak is found, repair it.
^ Oil pressure
If defective pressure is found, repair it.
2) Run engine for about half an hour at about 2,000 to 3,000 r/min., and then air will be purge and tapping sound will cease.
3) Should tapping sound not cease, it is possible that hydraulic valve lash adjuster is defective. Replace it if defective.
If defective adjuster can't be located by hearing among 16 of them, check as follows.
a) Stop engine and remove cylinder head cover.
b) Push adjuster downward by hand (with less than 20 kg or 44 lbs. force) when cam crest is not on adjuster to check if clearance exists between cam and adjuster.
If it does, adjuster is defective and needs replacement.