Symptoms of Failing Oil Pump?

[MrAguirrechu]

I'm having similar problems. Oil pressure was low and would bounce first thing in the morning. P0521 codes and CEL. Changed the sensor- after changing it only 3 years ago - and codes came back today. Has 205k on the engine. Thanks for the recommendation for checking the oil. I'll try that first.

 

[Plimbob]

Chris, what I meant by the 'sending unit' is the oil pressure sensor far back of the engine by the firewall. I can't recall exactly what brand it was but I don't believe it was AC Delco, I think it may have been Borg Warner. The oil level sensor (on the block by the starter) was AC Delco.

I took it for a drive last night, the pressure was lower than normal from the start but didn't start falling to really low levels (20psi) until I drove about 8-9 miles.

 

[iamdub]

Chris, what I meant by the 'sending unit' is the oil pressure sensor far back of the engine by the firewall. I can't recall exactly what brand it was but I don't believe it was AC Delco, I think it may have been Borg Warner. The oil level sensor (on the block by the starter) was AC Delco.

I took it for a drive last night, the pressure was lower than normal from the start but didn't start falling to really low levels (20psi) until I drove about 8-9 miles.

I see where the confusion is now. I didn't know any GenIV had the level sensor. Borg Warner should be a pretty reliable brand.

The change in pressure readings is likely temperature-related, but likely not the oil thinning out when heated. The O-ring could soften under heat and allow air in. I'd still do a proper O-ring test.

 

[Plimbob]

Update - I swapped the oil pressure sensor out. The warmed up oil pressure reflected now is about 30-32 at idle and about 42-44 at 65 mph 1800 rpm. It hasn't dropped below 28-30 since I changed it. I think it is resolved.

 

[Geotrash]

Update - I swapped the oil pressure sensor out. The warmed up oil pressure reflected now is about 30-32 at idle and about 42-44 at 65 mph 1800 rpm. It hasn't dropped below 28-30 since I changed it. I think it is resolved.

Thanks so much for following up, Tim.