Excessive Oil Consumption - MerCruiser GM4 Service Manual

Excessive Oil Consumption

1. Normal consumption.
2. Oil leaks
3. Oil too thin
4. Oil level too high
5. Drain holes in cylinder head plugged
6. Defective valve seals
7. Intake manifold gasket leaking
8. Worn valve stems or valve guides
9. Defective oil cooler (if so equipped)
10. Defective piston rings
11. Defective cylinders
12. Excessive bearing clearance
Index
90-816462 2-695
Cause Special Information
1. One quart of oil consumed in 5-15 hours of opera-
tion at wide-open-throttle (especially in a new or
rebuilt engine) is normal
2. Clean bilge, run engine with clean white paper on
bilge floor, locate oil leak(s)
3. Oil diluted or wrong viscosity
5. Oil will flood valve guides
9. Crack in cooler tubes
10. Glazed, scuffed, worn, stuck, improperly installed;
ring grooves worn; improper break-in; wrong end
gap
11. Out of round, scored, tapered, glazed; excessive
piston to cylinder clearance; cracked piston
TROUBLESHOOTING - 1C- 29