Why does oil pressure drop when the engine is hot?
Worn engine bearings cause perfect oil pressure during a cold start to plummet to near zero once the engine heats up or sits in neutral. Cleaning the oil pickup screen and replacing the O-ring may improve the initial cold pressure, but it will not prevent the pressure from eventually dropping back to zero as the engine reaches operating temperature.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Installing standard size bearings on the worn crank to temporarily bump up pressure and buy time.Did this help you?
- 2Verifying the dash sensor readings using a manual pressure meter.Did this help you?
- 3Cleaning the oil pickup tube screen and replacing the O-ringDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“The truck would before cold start at 20psi and stay there until it got hot then would drop to 0 after i dropped the oil pan and did clean the pick up screen and replace the o ring it cold starts at 40 but then drops to 20 then drops to 5 maybe even later on to zero”source ↗
“It is weird cause cold oil has perfect pressure like a new engine.”source ↗
“i also see that pressure is low when engine is hot and in neutral”source ↗
“I took only one bearing one to see if it is bad. It has wear but it is not terrible but it is far from good.”source ↗
Where this came up
People with this problem also raised
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- 2Why is my brake fluid empty with no leaks on the ground?