Well, your oil level sensor is working. Otherwise, it would be knocking on heavens door right now.

The pressure itself, that'* a tell-tale sign either the oil is very hot, or very old. Oil loses viscosity and the ability to maintain pressure when its very hot OR its very old/high mileage.

OR, it is possible that the sending unit is not seeing the pressure correctly. Have you noticed any oil leaks under the car recently? Or an abnormal amount of oil consumption?

You have 2 options. Either you can take it into a shop and have them install a oil pressure test gauge(or you can get one maybe at Autozone and do it yourself) and test the actual oil pressure. Or you can just plop down the $30 some dollars for a new oil pressure sending unit.

BTW, thank you for posting those videos. We would like to ask if we can use those 2 videos in our Techinfo section??

So far as I can tell, there are no oil leaks. When I check the oil it is a little over the max amount on the dipstick. The oil looks new. It is nice and clean. I am preparing to do an oil change as soon as some of this snow starts melting since I don't have a garage.


As for the mixing that my fiance was talking about, I checked the oil 4 times today and it is not mixing. I don't know what he was seeing. There is no residue on the oil cap or on the radiator cap.

If the oil was too hot, wouldn't the temp gauge be showing hot?


I will probably just go ahead and put in a new unit, seeing as how I already dumping a ton of money into this car with all the other crap I have had to do to it.


And yes, you can use the videos in your Techinfo section.


Thanks for the help and I will be sure to post updates.

Thank you.

Yes, please keep us updated.

Okay, after looking up this issue more and going to the gas station to get a pack of smokes I remembered something that might be important. There is a slight knocking sounds at start up but when you start going, it goes away until the next time you start it up. Could this be part of my oil situation?

I hope not. You can have 2 knocking type of sounds usually during first start up. Lower end knock or upper end knock(or commonly referred to as lifter tap).

The lower end knock, will sound more of a heavy metal thud than the tap tap tap noise of a lifter. The lifter tap will be much faster than the lower end knock. Which is usually associated with the connecting rods.

I'm beginning to wonder if the previous owner had a intake gasket issue and the coolant mixed in with the oil. That'* bad. Oil and coolant mixed together turns acidic, which has a tendency to eat at lower rod bearings.

Can you take any pictures of the upper intake plenum area? I'm looking to see if any work had been done to it recently.

when the intake was bad on my yukon it would knock when started for a while, turned out there was coolant in the oil(did not look like it on the stick it was liquidy when draining) after i changed the gaskets and cleaned up the engine and changed the oil it stopped. nothing white on the rad cap either but under the valve covers and in the intake there was a bunch

These engines are known for the oil pressure gauge failing, but they generally fail all the way up, or all the way down. Yours appears to be working as "normal". I had the same year bonneville a few bonnevilles ago, and my gauge moved similarly with the exception that it didn't get quite as low as yours. That type of movement of the gauge while driving and revving is normal, but your idle oil pressure looks low.

The first thing I've done on all four of my bonnevilles was replace the LIM and UIM gaskets. On every single one the LIM was in the beginning stages of failing and you could see the gasket deforming and broken in places. You wont have this issue with the new gaskets and if you don't know whether it'* been done or not, that would be my first recommendation is to get it done.

A little milky substance on the bottom of the oil cap is also normal this time of year and is caused by running the car for short periods of time and not warming it up all the way (typical behavior when sitting at a dealership). What you do not want to see is any milky substance on the dipstick when you pull it out or large gobs of it under the oil cab or in the valve cover.

A second opinion from one of our resident experts:

The only reason I'm hesitant to believe that the gauge is malfunctioning is your knocking on startup but that could be a separate issue. A mechanical gauge test is the only reliable way to determine what your oil pressure is actually at.

The knock is fast and is like a tapping noise. When inside the car you don't hear it unless the window is down. Also it sounds really close to the top of the engine. I will take pictures here in a few.

If the sound is a tapping noise, close to the top of the engine, and the oil pressure is low, I would think that the lifters are not getting oil, thus the tapping and low oil pressure.