Chevrolet 1980 Light Duty Truck Service Manual page 409

EXCESSIVE OIL CONSUMPTION DUE TO OIL ENTERING COMBUSTION
a. Check for intake and exhaust valve "O" ring seals
to be damaged, missing or loose. Repair or replace as
necessary.
b. Check for worn valve stems or guides. Repair as
necessary.
EXCESSIVE OIL CONSUMPTION DUE TO OIL ENTERING COMBUSTION
a. Check engine oil level too high. Correct as necessary.
b. Check for piston ring gaps not staggered and correct
as necessary.
c. Check for incorrect size rings installed and correct
as necessary.
d. Check for piston rings out of round, broken or scored
and replace as necessary.
e. Inspect insufficient piston ring tension due to engine
overheating and replace as necessary.
f. Check for ring grooves or oil return slots clogged and
corrected as necessary.
a. Check faulty oil gauge sending unit, and correct as
necessary.
b. Check for oil pump not functioning properly.
(Regulator ball stuck in position by foreign material) and
correct as necessary.
c. Inspect for excessive clearance at main and
connecting rod bearings and correct as necessary.
a. Check low oil level in oil pan and correct as
necessary.
b. Inspect leakage at internal oil passages and correct
as necessary.
c. Check oil pump suction screen loose or fallen off and
CHAMBER THROUGH HEAD AREA
CHAMBER BY PASSING PISTON RINGS
NO OIL PRESSURE WHILE IDLING
NO OIL PRESSURE WHILE ACCELERATING
ENGINE M E CHA NICAL
c. Inspect for plugged oil drain back holes in head.
Correct as necessary.
d. Inspect PCV system operation. Correct as necessary.
g. Inspect rings sticking in ring grooves of piston and
correct as necessary.
h. Inspect ring grooves worn excessively in piston and
correct as necessary.
i. Inspect compression rings installed upside down and
correct as necessary.
j. Check for excessively worn or scored cylinder walls
and correct as necessary.
k. Inspect oil too thin and replace if necessary.
1. Inspect mis-match of oil ring expander and rail and
correct as necessary.
d. Inspect for loose camshaft bearings and correct as
necessary.
e. Inspect leakage at internal oil passages and correct
as necessary.
correct as necessary,
6A-5
LIG H T T R U C K SER V IC E M ANUAL