I'm loosing pressure on the upper side. I've had the truck in the shop for the past week while trying to diagnose the problems. There is good pressure on the lower end but after it warms up, the top end starts loosing it's pressure and the sensor starts sounding. We've replaced the oil pump & the oil pressure sensor. The shop foreman at the GM dealership says he thinks is a cam bearing or lifter and thinks it's best to just replace the engine. I think they are missing something. this thing has been babied. We recently had a rear end accident and after repair, it started giving us the low oil pressure sensor. Anyone having this problem?

 

Hey TNBOLES I have an 03 tahoe and i had the same prob.I hate to be the bearer of bad news but the issue you are having is more than likely a spun bearing,and it is caused by the dex cool that gm uses for coolent.The stuff is junk and what happens is the dex cool causes your intake manifold gasget to blow and you loos the coolent into your engine.Well you might as well just poor a cup of sugar in your motor cause thats exactly what the efect is.this is exactly what happened to mine,which is in the shop having the engine replaced as we type.the only differance is i was loosing my pressure when i came to a stop it would drop to about 6 to 8 lbs. and my info center would start chimeing at me and tell me i had low oil pressure.It really baffled my mechanic and i because the engine ran just like the day i bought it when it held about 40 lbs at all times.well my mechanic changed the oil pump and the oil pump pickup tube oil ring which was bad as well, more than likely caused by the dex cool as well,but that didnt help.When he started the engine up it still had low pressure,so he took the oil pan back off and found metal shavings in the pan,so he looked up into the crank case and he could see the main berring had spun.I can almost bet u the dealership wont blame it on the dex cool tho.You can actually replace that motor for less than a grand if u just shop around on line a little bit thank god i just happened to buy an extended warranty and they covered it.just do me a favor and put regular antifreez in when u change the motor,just flush your heater core,and radiator really really good before adding the green stuff.Well i hope this info helped im sure not the pocket book tho,but at least maby it will give u some wear to start.and i also have a post going on this same sight its called low oil pressure in 03 tahoe feel free to check it out.

 

Welcome to the forum.

Wonder if he'd recommend a new engine if it was under warranty? I doubt it.

Does your engine make any sounds of distress at higher rpms? Has your coolant level changed recently? Since you just had work done before this started, I'd suspect something there if this happened immediately afterwards although not sure what it could be.

BTW in interest of full disclosure, any coolant including water in the oil will lunch an engine and Dex-Cool has nothing to do w/ it. The only problem I'm aware of associated w/ Dex-Cool is when someone adds an ethylene glycol antifreeze to it which makes it tend to gel.

Let's face it, if coolant made a good lubricant, we'd use water in the crankcase.

 

hey 73shark what im saying is the dex cool is the root cause of the prob.because its the dex cool that is causing the intake manifold gasgets to rot causing the leak into the engine itself causing the low pressure and the spun berrings.But yes you are wright that any other fluid in the oil is not a good lubricant its just that the dex cool is in my oppinion the cause of the gasgets failing,and the oppinion of other mechanic freinds of mine.