GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hi there, I am Cam. Can I get your first name please?I am sorry to hear about this issue. Can you tell me if you found ant debris in the oil pan when you did change the pump?
How long did you run the engine after replacement of the pump? Did you change any parts on the pick up or relief in the oil pan? Do you have a manual gauge that you can install and check to see if there is any pressure?
How low is very low?
Ok, at idle that is in spec so I am thinking we have another issue. Attached are the specs for this engine.
6 psig at 1,000 engine RPM
18 psig at 2,000 engine RPM
24 psig at 4,000 engine RPM
I am wondering if we have bad lifters then and not the oil pump. When it is running, do you have any misfiring?
Perhaps its something that was in the filter. What brand of filter did you use?
No, the pump is a matter of install, fill pan with oil and go from there.
Even priming is not really needed. I only prime the system when installing a brand new engine.
Myself I would install a manual oil pressure gauge in place of the sensor and verify low pressure. If so then I would check at the oil filter. If still low then back into the pump to verify its not faulty. If you have oil pressure but the noise remains then I would be looking at lifters themselves. I would also be opening the filter and looking for debris.
Linus, my worry is that some debris was in the oil filter and plugged up the block. in the picture attached you will see the diagram of how the oil flows.
I would remove the oil filter and the oil pressure sensor. Try pushing compressed air back from the sensor and flush what ever is plugging it from the filter. If you get nothing Then remember the block in the side of the engine block by the filter.
Just above the filter is a small block that is a cover with 2 bolts, about 2" long. It's where an oil cooler would attach if you had one.
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