low oil pressure in a 5.0 ford engine with 76,000 miles
Asked by GuruDYY9C Aug 12, 2017 at 10:14 AM about the 1990 Ford F-150 XLT Lariat SB
Question type: Maintenance & Repair
good oil pressure until it warms up, the engine does have a burnt valve in it, if I give it a little gas the pressure is back to normal, but if I let it idle no oil pressure
2 Answers
Have you actually measured the oil pressure with a mechanical gauge?
CharlieC0522 answered 5 years ago
I had the problem on my 2012 F150, 5L engine, when the engine gets to operating temp and I stop at a red light with the trans in Drive, the Oil Warning light comes on. Maybe even go On and Off but raising the engine RPMs raised the oil pressure. A mechanic explained that the RPMs can not be adjusted manually because the computer controls the gas flow to match the air intake flow. So if the air is restricted the RPMs will drop. At idle the reduced RPMs result in less output from the oil pump which then can result in tripping a "low oil pressure warning". Replacing a dirty air filter ( about $20) fixed my problem.
