Abnormal Noise Due To Hydraulic Lash Adjustor; Troubleshooting Procedure - Isuzu C22NE Workshop Manual

Abnormal Noise Due to Hydraulic Lash Adjuster
Should abnormal noise due to the hydraulic lash
adjuster trouble be heard immediately after the engine
is started, inspect as follows:
Condition
Abnormal noise is heard
HLA is spongy
Valve clearance is not zero

Troubleshooting Procedure

Short out each spark plug in sequence using insulated
spark plug wire removers. Locate cylinder with
defective bearing by listening for abnormal noise that
stops when spark plug is shorted out.
Condition
Noise from connecting rods or
from connecting rod bearings
(Faulty connecting rods or
connecting rod bearings usually
make an abnormal noise slightly
higher than the crank bearing
noise, which becomes more
evident when engine is
accelerated)
Troubleshooting Procedure
Abnormal noise stops when the spark plug on the
cylinder with defective parts is shorted out.
Condition
Piston and cylinder
(Faulty piston or cylinder usually
makes a combined mechanical
thumping noise which increases
when engine is suddenly
accelerated but diminishes
gradually as the engine warms up)
Possible cause
Air contaminated
Check ball valve broken
Safety valve in cylinder head
broken
HLA inside stick
Possible cause
Bearing or crankshaft pin worn
Crankpin out of round
Connecting rod bent
Connecting rod bearing seized
Possible cause
Piston clearance increased due to
cylinder wear
Piston seized
Piston ring broken
Piston defective
ENGINE DIAGNOSIS (C22NE, 22LE, 20LE) 6-9
Correction
Bleed
Repair
Replace
Replace HLA assembly
Correction
Replace connecting rod bearings
and crankshaft or regrind
crankshaft and install the under
size bearing
Replace connecting rod bearings
and crankshaft or regrind
crankshaft and install the under
size bearing
Correct or replace
Replace connecting rod bearings
and crankshaft or regrind
crankshaft and install the under
size bearing
Correction
Replace piston and cylinder body
Replace piston and cylinder body
Replace piston and cylinder body
Replace pistons and others