Low engine oil pressure problems usually get worse when the engine warms up, not the other way around. SureTrack community member bmaples had a Chevrolet Silverado in the shop where the engine oil pressure would be low when the engine was cold but improve once it warmed up. They posed the question to the community, and with the help of fellow community member Jamesbellam and others, they were able to resolve the issue quickly.
The following Community Fix summarizes the interaction between members of the community that led to the solution.
2005 Chevrolet Silverado 1500 5.3L
Low oil pressure when cold, replaced bad O-ring.
Customer complains that Low Oil Pressure warning comes on when engine is cold or sits for hours.
Diagnostic Steps Performed/Parts Replaced
Let truck sit overnight and started it up. Shortly after starting, or if vehicle sits for 4 to 6 hours, the oil pressure will go below 5 psi and LOW OIL PRESSURE warning message will illuminate on dash. Bring up RPM and it will raise up to 30 to 35 psi. After reaching operating temperature the oil pressure will sit at 10 psi at idle, or a bit under, but will still raise to 30 plus when RPM increased. Engine never makes any bad noise like lifter tap or knock. Module scan revealed no codes. Live data confirms pressure does drop and sits at 9.7 to 10 psi at idle when warmed up. Replaced oil pressure sensor and no change. We’ve confirmed this with a mechanical gauge in place of oil filter. Truck has a Jasper engine with 150k miles on it that we replaced about 5 years ago. Truck itself has 404k miles. Is this an oil pump problem or just a worn engine? Guy is on time with oil changes and uses Delco filters. Any tips or guidance is greatly appreciated.
Best Answer from Community Member Jamesbellam
Drop oil pan inspect pickup and any O-rings. Remove and inspect main bearing caps for damage or scoring. Measure bearing oil clearance with plastic-gauge. Repeat for rod bearing caps. Hope this helps.
Jasper gave a way to test for the pick up tube seal. Add three quarts motor oil over fill line on stick and re check. If pressure improves then it’s a pick up problem. If pressure doesn’t improve then likely the Oil Pressure Control Valve on the oil pump or worn main bearings is the problem. Did this test and pressure improved. Be sure to drain excess oil after test or during repair.
Replaced O-ring on oil pump pick up tube. Let truck sit until cold and retested oil pressure and it is back to normal.
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