Oil pressure

RACHEL MEREDITH

MEMBER
1997 FORD F-150
V8
4WD
AUTOMATIC
307,000 MILES

Ingine has sudden total loss of oil pressure upon switching engine off and restarting has total regain of oil pressure. When engine looses oil pressure it becomes mechanically noisy. This total loss of oil pressure can happen within 1-15 mins of engine running and upon switching motor off and restarting total regain of oil pressure and mechanical noises go away. What could be causing this syptom?

Saturday, January 22nd, 2011 AT 8:51 PM

1 Reply

ERNEST CLARK

MECHANIC
1,730 POSTS

Once your engine is started, the pump begins circulating oil from the pan to the rest of the engine. If it's low on oil, not enough oil will fall back to the pan so the pump will begin circulating air, dropping oil pressure. Also, if there's lots of sludge in the cylinder head, it won't let the oil drain back to the pan in time to get picked up by the pump, again causing the same problem as above. Once you cut the engine off for a while, the oil finally drains back down, but the process is repeated when you restart the engine.

Finally, there could a debris (metal) in the pan that will clog the oil pump pick up tube or an oil passage.

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Wednesday, February 16th, 2011 AT 12:20 PM