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SERVICE DIAGNOSIS - PERFORMANCE (CONT.)
ENGINE
9 • 9
C O N D I T I O N
P O S S I B L E C A U S E S
C O R R E C T I O N
OIL PUMPING AT
RINGS—SPARK PLUGS
FOULING
• Worn, scuffed or broken rings
• Carbon in oil ring slot
• Rings fitted too tight in grooves
• Leaking intake gasket
• Worn valve guides
• Leaking valve guide seals
• Hone cylinder bores and install new rings.
• Install new rings.
• Remove the rings. Check grooves. If groove is
not proper width, replace piston.
• Replace gasket and tighten to the proper
specifications.
• Ream guides and replace valves with oversize
valves and seals.
• Replace seals.
J9009-121
INSPECTION FOR ENGINE OIL LEAKS
I f an o i l leak source is not r e a d i l y identifiable, the
following steps should be followed:
(1) A t t a c h a n a i r hose w i t h pressure gauge a n d
regulator to the dipstick tube.
(2) Disconnect the breather cap t o a i r cleaner hose
at the breather cap end. Cap or p l u g breather cap
nipple.
(3) Remove the P C V valve f r o m the cylinder head
cover. Cap or p l u g the PCV valve grommet.
(4) After the engine is sealed, set t h e a i r pressure
regulator N O H I G H E R t h a n 27 k P a (4 psi).
(5) U s i n g a l i q u i d soap solution or preferable a
stethoscope, inspect a l l suspected o i l leak areas. I f an
o i l leak area is detected, repair per the service man-
u a l instructions.
(6) I f no leaks are detected, t u r n off t h e a i r supply
and remove t h e a i r hose and a l l plugs. I n s t a l l t h e
PCV valve and breather cap hose. See step 7 and
check for higher pressure leaks o c c u r r i n g d u r i n g nor-
m a l engine operation.
(7) Clean the o i l off the suspect o i l leak area using
a suitable solvent. D r i v e t h e vehicle
a t various
speeds approximately 24 k m (15 miles). Check t h e
engine for signs of a n o i l leak. I f a n o i l leak i s found,
repair per the service m a n u a l i n s t r u c t i o n s .
(8) I f the leakage occurs a t the crankshaft rear o i l
seal:
(a) Raise the vehicle.
(b) Remove torque converter or clutch housing
cover and inspect rear of block for evidence of o i l .
A circular spray p a t t e r n generally indicates seal
leakage.
Where
leakage tends t o r u n s t r a i g h t
down, possible causes are a porous block and the
rear cam and galley plugs. See Group 9, Engines
(Rear M a i n B e a r i n g O i l Seals), for the proper seal
(and retainer) i n s t a l l a t i o n .
(c) I f no leaks are detected w h i l e the crankcase
is pressurized 27 kPa (4 psi), very slowly t u r n the
crankshaft and watch for leakage. I f a leak is de-
tected w h i l e t u r n i n g t h e crankshaft, i t s possible
the crankshaft seal surface is damaged i n the seal
area, m i n o r nicks or scratches can be polished out
w i t h emery
cloth. See Group 9, Engines
(Rear
M a i n B e a r i n g O i l Seals), for the proper seal (and
retainer) i n s t a l l a t i o n .
CHECKING ENGINE OIL PRESSURE
(1) Remove o i l pressure sending u n i t w i t h Tool C-
4597).
(2) I n s t a l l o i l pressure l i n e a n d gauge (Tool C-
3292). S t a r t engine and record pressure. Refer to en-
gine
specification
(engine
lubrication) for proper
pressures.
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