2004 Gmc 5.3 Low Oil Pressure

[Titen]

I have a question in the E&P Tech section, but after searching the forums and reading all the posts on this subject I thought this might be a better place for my concerns.

 

My '04 GMC Sierra (5.3L, Mobil1, GM filter, 94k, well maintained ) just started getting a low oil press indication and warning when below 1000rmp, when starting cold it will be high enough to keep the warning off for about 30 seconds and then drop off. I changed the oil and filter, same problem. I took it to a local dealer and they put a mechanical gage on and verified actual low pressure. They dropped the pan and found no obvious problems. They then replaced the oil pump, when they put it back together and started it they had the same low oil pressure problem. I don't want them to get into 'shotgun troubleshooting' , do you have any suggestions?

 

Thanks, Tim

[Titen]

Well...., I didn't get any response, but if anyone is interested, they dropped the pan again and 'noticed' a cam bearing migrating out of it's bore. New engine, many dollars. I am not real happy with the dependability of these new engines.

[Draenor]

One problem would be a blocked oil passage. Another would be bad bearing clearance. I assume the dealer checked the oil pump clearances?