INSTALLATION
(1) The valve stem seal/valve spring seat should be
pushed firmly and squarely over the valve guide
using the valve stem as guide. Do Not Force seal
against top of guide.
(2) Install valve spring. (Refer to 9 - ENGINE/
CYLINDER HEAD/VALVE SPRINGS - INSTALLA-
TION)
HYDRAULIC LASH
ADJUSTERS
DIAGNOSIS AND TESTING - HYDRAULIC LASH
ADJUSTER NOISE DIAGNOSIS
Proper noise diagnosis is essential in locating the
source of a NVH complaint. Locating a lash adjuster
(tappet) type noise can sometimes be difficult. As a
result, an initial misdiagnosis may occur.
Refer to LASH ADJUSTER (TAPPET) NOISE
CHART indicating possible lash adjuster (tappet)
noise sources and possible sources that could lead to
a misdiagnosis.
Refer to LASH ADJUSTER (TAPPET) NOISE
CHART for possible causes and correction of a lash
adjuster (tappet) type noise.
LASH ADJUSTER (TAPPET) NOISE CHART
POSSIBLE CAUSES CORRECTION
1. Engine oil level—too high or too low. This may cause
aerated oil to enter the adjusters and cause them to be
spongy.
1. Check and correct engine oil level.
2. Insufficient running time after rebuilding cylinder
head.
2. Low speed running of up to 1 hour may be required
to fully evacuate trapped air from the valve train
system. During this time, turn engine off and let set for
a few minutes before restarting. Repeat this several
times after engine has reached normal operating
temperature.
3. Air trapped in lash adjuster (after 1 hour run time). 3. See below:
(a) Check lash adjusters for sponginess while installed
in cylinder head. Depress part of rocker arm over
adjuster. Normal adjusters should feel very firm. Very
spongy adjusters can be bottomed out easily.
(b) If lash adjuster(s) are still spongy, replace with new
adjuster/rocker arm assembly.
4. Low oil pressure 4. See below:
(a) Check and correct engine oil level.
(b) Check engine oil pressure.
(c) Check for excessive bearing clearance and correct.
(d) Check for worn oil pump.
5. Oil passage to cylinder head(s) plugged with debris. 5. Check cylinder head oil passages and cylinder head
gasket restrictor for blockage. Clean or replace as
necessary.
6. Worn valve guide(s). 6. Ream guide(s) and replace valve(s) with oversize
valves and seal(s).
7. Air injested into oil due to broken or cracked oil
pump pickup tube.
7. Inspect pickup tube and replace as necessary.
8. Collapsed lash adjuster due to debris injestion. 8. Clean debris from engine and replace lash
adjuster(s).
LH ENGINE 2.7L 9 - 37
VALVE STEM SEALS (Continued)