Cylinder-To-Water Jacket Leakage Test; Lash Adjuster (Tappet) Noise Diagnosis; Visual Test Method; Cooling System Tester Method - Chrysler 2000 LHS Owner's Manual

9 - 18 2.7L ENGINE
DIAGNOSIS AND TESTING (Continued)
section. An engine cylinder head gasket leaking
between adjacent cylinders will result in approxi-
mately a 50–70% reduction in compression pressure.

CYLINDER-TO-WATER JACKET LEAKAGE TEST

WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING WITH COOLANT PRES-
SURE CAP REMOVED.

VISUAL TEST METHOD

With the engine cool, remove the coolant pressure
cap. Start the engine and allow it to warm up until
thermostat opens.
If a large combustion/compression pressure leak
exists, bubbles will be visible in the coolant.

COOLING SYSTEM TESTER METHOD

WARNING: WITH COOLING SYSTEM TESTER IN
PLACE, PRESSURE WILL BUILD UP FAST. EXCES-
SIVE PRESSURE BUILT UP, BY CONTINUOUS
ENGINE OPERATION, MUST BE RELEASED TO A
SAFE PRESSURE POINT. NEVER PERMIT PRES-
SURE TO EXCEED 138 kPa (20 psi).
POSSIBLE CAUSES
1. Engine oil level—too high or too low. This may cause
aerated oil to enter the adjusters and cause them to be
spongy.
2. Insufficient running time after rebuilding cylinder
head.
3. Air trapped in lash adjuster (after 1 hour run time).
4. Low oil pressure
LASH ADJUSTER (TAPPET) NOISE CHART
Install Cooling System Tester 7700 or equivalent to
pressure cap neck. Start the engine and observe the
tester's pressure gauge. If gauge pulsates with every
power stroke of a cylinder a combustion pressure
leak is evident.
CHEMICAL TEST METHOD
Combustion leaks into the cooling system can also
be checked by using Bloc-Chek Kit C-3685-A or
equivalent. Perform test following the procedures
supplied with the tool kit.

LASH ADJUSTER (TAPPET) 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 the following 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.
CORRECTION
1. Check and correct engine oil level.
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. 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. 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.
LH