I have a 2003 Silverado with 85,000 miles that runs perfect. The other day out of nowhere when I went to start the truck the oil pressure guage maxed out before I ever even started the engine (the key was in on position just before turning over motor) I thought they did not get oil pressure until the truck was on?? Also once I turn on the engine and the truck is running the guage stays maxed out. I am not sure what to do about this as the oil seems fine and is changed regularly the truck is still running fine. Does anyone have any ideas I would greatly appreciate any input. Thanks so much

 

Dude, my truck is the same way... I have an 05. Since I bought it the truck runs maxed out. However, I should say that I DO have an oil leak which I hope is the pan gasket or whatnot. My truck runs perfect though, haven't had any issue's with regards to the oil pressure being maxed out.

 

I have had the same issue on my 2004 Silverado, now fixed.
Mine started with what appeared to be a short in a wire or a bad sending unit. Occasionally while driving the gauge would rise up to max (sometimes so high that it pointed almost straight down) then go right back down to normal. Finally it maxed out all the time
The good news, there is most likely nothing wrong with the oil pressure, so you’re not risking engine damage by driving!
As you said, the gauge maxed out when the ignition is set to ‘on’ but the truck is not started. So, you are correct, if it’s not running, there is no oil pressure. It’s a faulty display (but you’ve already guessed that).
Now the bad news, it’s a digital dash.
Yes, I know, it’s all gauges with orange needles, so it looks like it’s not digital -- but it’s a totally computerized dash, just like all modern cars are now. Even the classic throttle cable is a thing of the past. Look down by your ‘gas’ peddle – at the top where there is normally a metal cable connecting the gas peddle to the throttle on the engine. You won’t find a cable, just wires. The gas peddle now works like a dimmer switch for the lights in dining room. All electric, and the computers does it all. But I digress.
The gauges, instrument cluster, or whatever you want to call it, is most likely the problem. When the board begins to fail, one or two of the gauges can go crazy. And the entire cluster must be replaced. -BUT- before you run out and spend a few hundred on a new one, it could also be as simple as a bad oil pressure sensor (oil pressure sending unit), a bad connector, or a broken wire between the sensor and one of the many computers controlling the truck (ECM I think)
Assuming no warning lights are on when, it points even more to a partial failure of the instrument cluster. If you are lucky enough to be able to find one cheap at a salvage yard, or have a really good friend with the same cluster, you can try swapping them to see if the problem follows the display or the truck.
-NOTE- some clusters need to be programmed to the vehicle. I believe the 03-08 do NOT need programming to operate, but let’s get an expert opinion from a GM tech like ‘ShawnVW’ before you start tearing your truck apart for a minor problem
I was fortunate to have mine fail under warranty, the dealer changed the interment cluster, and the oil pressure has been accurate ever since.
More good news, it’s not the speedometer! So it’s not the most important part of the display!
My ’03 also started acting up last year. I was driving about 10 in the parking lot at work, the speedometer suddenly jumped to 30. On the way home, my speed showed about 80 in a residential neighborhood. I assure all the parents out there, I have WAY to much respect to ever do that. My best guess was doing about 30mph. At a red light, or even in park & was ‘moving’ 20-40mph. Oh, sorry, my point-- I tried a little test to figure out where to start. I set the cruse to what felt like 30, 40, then 50. The truck held the speed fine, even though the speedometer showed several erratic changes in speed. This rules out the very complex Hz driven VSS. The cruse & the speedometer receive their speed signals form basically the same source. One works, the other dose not, so I know it’s the interment cluster or a short in a wire close to it.
Here’s a little ray of hope. It had it’s little tantrum on and off for about 2 weeks, then suddenly stopped and has not done it since.
Hope this helps, and good luck to ya!

 

If oil pressure too high then therorectolly it would blow off the oil filter,if too high and in doubt hook up a tester in a idling position a 30psi is good and 2000/2500 rpm 40-60 psi is for me best ,readings may vary from engine ware to types of oil pumps IE: high pressure/high volume ect ...

for the fun

 

Chevy Girl,
There was a recall on the instrument cluster a couple of years ago. My gauges went wild, all of them. Don't know if the recall is still in effect, but , you could call a Chevy dealer and see if you can get one replaced for free. When i called called they stated that i could not have over 60,000 miles. But i own a 2003. You might want to give it a try.

 

Insrument cluster is going bad. Chevy used cheap stepper motors and they are known to fail. Try the dealer, if you can't get any help there, you might try a refurbish shop. They can replace the stepper motors and recalibrate all the gauges for under $100. Good luck!

 

I've got 195,000 miles on my '03 and my oil pressure gauge just started doint the same thing. I cant decide if I should try a new sending unit and see if that fixes it or just put a mechanical gauge in. If I unplug the oil pressure sending unit will it cause the check engine light to come on/stay on.

 

Also, is there a way to test the sending unit just to make sure that it may or may not be the cause of the problem???

 

My bet is the sending unit, to my knowledge the only way of checking one would be with a mechanical gauge to see if they read the same. I had this problem with my Jeep, the first new sending unit was DOA exchanged it for another new one and haven't had a problem since.

 

Just so you guys know, the first thing I did was to change the sending unit. What a PITA. I like to throw a beat'in to ever came up with that design. The problem still existed. Chevy trucks and SUV's have a well documented history of instrument cluster failure. If you get the cluster rebuilt you should be all set.