Cessna 177 SERIES Service Manual page 161

11-35.
TROUBLE SHOOTING (Cont).
TROUBLE
PROBABLE CAUSE REMEDY
HIGH OIL PRESSURE. High viscosity oil.
Drain sump and refill with proper
grade and quantity of oil.
Relief valve defective. Remove and check for dirty or de-
fective parts. Clean and install;
replace valve if defective.
Defective oil pressure gage. Check with a known good gage. If
second reading is normal, replace
gage.
/
LOW OIL TEMPERATURE. Defective oil temperature gage
Check with a known good gage. If
or temperature bulb. second reading is normal, replace
gage. If reading is similar,
the temperature bulb is defective.
Replace bulb.
Oil cooler thermostatic
Remove valve and check for proper
valve/bypass valve defective
operation. Replace valve if defec-
or stuck.
tive.
HIGH OIL TEMPERATURE.
Oil cooler air passages clogged.
Inspect cooler core.
Clean air passages.
Oil cooler oil passages clogged. Attempt to drain cooler. Inspect
for sediment. Remove cooler and
flush thoroughly.
Thermostatic valve or bypass
Feel front of cooler core with hand.
valve damaged or held open
If core is cold, oil is bypassing
by solid matter. cooler. Remove and clean valve
and seat.
If still inoperative, re-
place.
Low oil supply. Check with dipstick.
Fill sump
with proper grade and quantity
of oil. Refer to Section 2.
Oil viscosity too high. Drain sump and refill with proper
grade and quantity of oil.
Prolonged high speed operation Hold ground running above 1500
on the ground. rpm to a minimum.
Defective oil temperature gage.
Check with a known good gage.
If second reading is normal.
Replace gage.
Defective oil temperature bulb.
Check for correct oil pressure, oil
level and cylinder head tempera-
ture. If they are correct, check
oil temperature gage for being de-
fective: if similar reading is ob-
served. bulb is defective. Re-
place bulb.
Change 2 11-15