Engine
SHOP MANUAL
Ch 1 page 233
Low oil pressure
Eect Cause Trouble shooting Action
Gauge shows low
pressure
Defective sensor/instru-
ment
Take a reading of the oil pressure on warmed-up
engine using a mechanical pressure gauge directly
on the engine:
Minimum 1 bar at 800 r/min.
Maximum 6 bar > 800 r/min.
Obs! Single-speed engines must not be tested
at 800 r/min. Risk of damage to the exi -
ble coupling
Incorrectly adjusted oil
relief valve
- 1 shim = 0.2 bar
(screw adjustment on
14-series engines)
Broken spring in oil
relief valve (14-series
engines, earlier version)
Max. oil pressure 2 bar
at 2000 r/min
- Check/remedy
relief valve
The piston in the oil
relief valve has jammed
in open position
Gauge shows low
pressure
Loosened guide plates in
the oil cooler prevent
passage of the oil
Worn/damaged oil pump
Plug in cylinder block
under the relief valve
has come loose (11-
series engine)
Clogged oil cooler
Seized/worn bearings in
compressed air compres-
sor, see Compressed air sys.
Pressure varies when
compressor charges/
relieves
Loose screws in timing
gear’s intermediate gear
Gauge indicates low
pressure at maxi-
mum speed but not
at idling speed
The main oil duct (to
piston cooling nozzles)
plug in the rear of the
engine has come loose
(also at front of engine,
9-series engine)
Oil pressure at idling/
low engine speed is not
aected since the deliv-
ery valve closes at 3 bar
No oil pressure at
idling speed
(14-series engine)
Oil valve sleeve screwed
out of oil pump housing
(gives “by-pass” and
disables the overow
valve)
Check that the oil
valve sleeve is correctly
tted
- Tighten the oil valve
sleeve
- If damaged, change the
sleeve
Crankshaft bearing/main
bearing of wrong size
has been tted on
reground crankshaft
Max. oil pressure 2 bar
also when engine cold
- Change to bearings of
the correct size. Check
the bearing seats before
assembly
Excessive play in big-
end and main bearings
Seizing in camshaft
bearings
If the bushing slides all
the way out of the bear-
ing seat, the oil pressure
warning lamp will come
on.
The engine throws out
oil through the crank-
case ventilation
Piston cooling nozzle
has come loose
Seizing in the bearing on
engine power take-o
ED140 (14-series engine)
Oil pressure can be
increased ~ 1 bar when
the power take-o is
under load
Loosened oil duct plugs
at camshaft bearing
seats, under
the protection plate in
the V (14-series engine)
Pressure drops to 0 bar
Suction pipe to oil pump
has come loose, the
pump sucks air
Engine too hot
Extremely low lubricat-
ing oil viscosity
- Choose a viscosity that
is suitable for the ambi-
ent temperature
Worn bushings or loose
shaft in oil cleaner
- Change rotor if bush-
ing is worn oval
- Change worn/dam-
aged shaft
Broken O-ring on
cyclone part of oil
cleaner
Defective oil pump drive
Internal leakage in oil
cleaner
Ch
eck that the oil
cleaner is correctly
assembled
Loosened guide plates in
the oil cooler prevent
passage of the oil
Worn/damaged oil pump
Plug in cylinder block
under the relief valve
has come loose (11-
series engine)
Clogged oil cooler
Seized/worn bearings in
compressed air compres
sor, see also page
Pressure varies when
compressor charges/
relieves
Loose screws in timing
gear’s intermediate gear
Continuation next page
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