1B-6 AIR CONDITIONING (OPTIONAL)
SH410
DIAGNOSIS OF ABNORMAL NOISE
There are various types of noise, ranging from those produced in the engine compartment to those from the pas-
senger compartment, also from rumbling noises to whistling noises.
ABNORMAL NOISE FROM COMPRESSOR
Condition Possible Cause Correction
During compressor operation, a
rumbling noise is heard propor-
tional to engine revolutions.
Inadequate clearance in piston
area (piston or swash-plate).
Repair or replace compressor as
necessary
A loud noise is heard at a certain
rpm, disproportionately to engine
revolution.
Loose or faulty V-belt.
Loose mounting bolts.
Adjust V-belt tension, or replace
belt.
Retighten mounting bolts.
A loud rattle is heard at low en-
gine rpm.
Loose compressor center bolt. Retighten center bolt.
Replace compressor if it was op-
erated in this condition for a long
time.
ABNORMAL NOISE FROM MAGNETIC CLUTCH
Condition Possible Cause Correction
A rumbling noise is heard when
compressor is not operating.
Worn or damaged bearings. Replace bearings.
A chattering noise is heard when
compressor is engaged.
Faulty clutch gap (excessive).
Worn clutch friction surface.
Compressor oil leaked from shaft
seal, contaminating the friction
surface.
Adjust clutch gap.
Replace clutch.
Replace compressor shaft oil seal.
ABNORMAL NOISE FROM TUBING
Condition Possible Cause Correction
A droning noise is heard inside
vehicle, but not particularly no-
ticeable in engine compartment.
Faulty tubing clamps.
Resonance caused by pulsation
from variations in refrigerant pres-
sure.
Reposition clamps or increase the
number of clamps.
Attach a silencer to tubing, or
modify its position and length.
ABNORMAL NOISE FROM CONDENSER
Condition Possible Cause Correction
Considerable vibration in con-
denser.
Resonance from condenser
mounting stay and body.
Firmly insert a silencer between
condenser mounting stay and
body.
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