2005 Suburban has a low oil pressure warning

I have had a low oil pressure alarm on my 2005 Suburban on several occasions. Only when cold, and when idling. My mechanic has checked everything out and says he can fond no problem. Replaced the oil pressure sending unit. Still happens - though not always.
The vehicle has 248,000 miles on it and it runs perfectly, but I am concerned about this warning. Anyone have any thoughts? I’d like to keep it running well and we take long road trips. Don’t want a disaster!

Have your mechanic replace the oil level sensor switch.


Thanks! Is that sensor different than what he called “the sending Unit”? He said he replaced the “sending unit”.

The oil pressure sensor is different than the oil level sensor.

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Please clarify what “checked everything out” means

Engine oil level is correct?

He hooked up a mechanical oil pressure gauge, and everything was within specs?

Did he provide you with the readings?

Low oil pressure or low oil level? There’s a huge difference.

I thought he was talking about the oil pressure sending unit being replaced which would make sense. If its the oil level sensor, pretty easy to tell if that’s malfunctioning or not. Just check the oil. At any rate at 250K, there is likely some engine wear that is causing an intermittent low pressure, particularly at low rpm. If engine wear not much to do about it unless you want to put a new short block in. What you can do though is have a secondary manual oil pressure gauge installed. Then you can see exactly what is happening with the pressure at various times to determine if its time to start thinking about trading or replacing the engine.

Thanks! It doesn’t burn oil at all at this point. My major concern would be a catastrophic oil pump failure. But no abnormal noise at idle or otherwise.

Oil level always normal.

Yes to all of the above. Didn’t give me a printout of the manual gauge readings but gave them to me verbally.
Just hoping the oil pump isn’t going out. But at cruise on the highway the pressure reads normal all the time.

Assuming the oil pressure truly is low . . . at times, apparently . . . I don’t think it’s going to be the oil pump

I think it would be due to engine wear . . . not surprising given 248K miles

Do you remember what they were . . . how many psi, and at what rpm?

Hi, I own a 2007 Chevy Surburban Z71, i’ve had a low oil pressure problem last year, BTW, I have 204,000 miles on my truck, and I discovered that the oil pump o ring was damaged, causing the low oil pressure issue.

Good to know. What had to come off to get to that o-ring?

I had to remove the front timing cover and drop the oil pan.

saw the o-ring mentioned on tv rod show when they did an LS swap. seems the oil pickup tube is usually installed with little care when they change the oil pan for different cars.