Hello all, could I get some help with my oil presure. I am racking my brain to figure out what the problem is.

The details
I have a 99 Sierra 5.3L V8 2W drive I think that is all relevant infomation.

Last week I took the truck into local mechanic for an oil change. Had a problem with getting the "Oil Change" Message from turning off. This I didn't notice until making it home. Couple hours later went to drive away and noticed oil pressure gauge is reading 65PSI idling. and went to 80 or so on accelerating engine.

Did the easy things like change the oil and filter over again. The presure came down at idle but still reaches 80Psi on accelerating engine. Just changed the oil presure sending unit because of the hassile of putting a mech. gauge on it. That was not the problem so I put the mechanical gauge and tested it at idle there is 45Psi but still like 75 at 3000RPM

I don't know if i should just change the oil pump. Or is there something that I am overlooking.

Thanks
Leonard Baxter

Usually you don't hear people complaining about too much oil pressure, but that can cause oil leaks and other oil usage concerns.
Your oil pump pressure regulator valve may be sticking

Yea I know what some luck on my part. I figured that was the next thing that could be wrong. I wanted to know if anyone had anything else to add.

One other thing is the regulator valve inside the oil pump or is it some where else. I have seen it go both ways.

I have a 99 gmc sierra 1500 5.3l I notice the high oil pressure my self. Its not just your truck. First year gm went with these models so could just be a flaw they didnt correct until later models. I wouldnt worry to much about it unless it sits at 80 when idling. then there is a problem.

Hello all, could I get some help with my oil presure. I am racking my brain to figure out what the problem is.

The details
I have a 99 Sierra 5.3L V8 2W drive I think that is all relevant infomation.

Last week I took the truck into local mechanic for an oil change. Had a problem with getting the "Oil Change" Message from turning off. This I didn't notice until making it home. Couple hours later went to drive away and noticed oil pressure gauge is reading 65PSI idling. and went to 80 or so on accelerating engine.

Did the easy things like change the oil and filter over again. The presure came down at idle but still reaches 80Psi on accelerating engine. Just changed the oil presure sending unit because of the hassile of putting a mech. gauge on it. That was not the problem so I put the mechanical gauge and tested it at idle there is 45Psi but still like 75 at 3000RPM

I don't know if i should just change the oil pump. Or is there something that I am overlooking.

Thanks
Leonard Baxter

I have the exact same problem with my '99 Sierra!! We (us 3 guys)should compare notes and maybe approach GM as a group to see if the GM engineers can figure out what is causing the higher than normal oil pressure.

My 5.3L engine has just over 40k miles on the clock and I've been using Mobil1 5W30 synthetic oil since about 7k miles. I always use AC Delco PF59 oil filters. Even though I use synthetic oil, I still change it when the change engine oil light comes on, usually between 4-5k miles.

The oil pressure used to stay between 40-65psi. About a year ago, it started creaping up to just over 70psi, and now it will sometimes hit 80psi even when driving at low 45mph speeds. I replaced the oil pressure sensor, but that didn't fix the problem. I took the truck to the GMC dealer last month to get it checked out. The mechanic looked it over and was also left scratching his head. He called the GM tech assistance line and here was their response:

"The mechanically measured oil pressure is within GM specs and GM will not and can not do anything unless the oil filters start blowing off the engine or something else breaks"

Since this is the vehicle my family uses for travel, I told the dealer that I no longer trusted taking the vehicle out of town waiting for something to break that could leave us stranded. I got a blank stare back in response and here we are. Then GM wonders why people don't wnat to buy their products any more.

Can you provide some specifics like mileage and type of oil/filter used on your truck so we can compare notes? It would be nice to get this resolved before the engine starts blowing oil seals out or worse.

Thanks....!