08 Silverado Low Oil Pressure?

hubob · October 11, 2009

I just replaced the oil pump in my 08 Silverado 5.3L and I still have low oil pressure according to my dash gauge. It doesnt sound like it has low oil pressure. When its cold its fine but once it heats up at every stop or get below 1000rpm the low oil pressure indicator comes on. An suggestions?

redvett · October 11, 2009

I am puzzled why you messing with your truck unless you have over 100K on it, its under warranty let GM fix it.

I just replaced the oil pump in my 08 Silverado 5.3L and I still have low oil pressure according to my dash gauge. It doesnt sound like it has low oil pressure. When its cold its fine but once it heats up at every stop or get below 1000rpm the low oil pressure indicator comes on. An suggestions?

desrtrat · October 11, 2009

also check for bad sending unit. put a mechanical gauge and see what that reads..

good luck

Nytemare · October 13, 2009

what kind of oil do you use.

Sometimes cheep oil doesn't make good oil pressure.

stlavsa · October 13, 2009

what kind of oil do you use.

Sometimes cheep oil doesn't make good oil pressure.

Cheap oil wouldnt have anything to do with it.. IF the oil was too thin it could do it, butttttttttt it already calls for 5w30 which is pretty thin, and its an 08 I wouldnt assume the bearings are worn much yet.. so I would guess the problem is something else.

Like posted previously, why isnt it at the GM dealer?

Nytemare · October 13, 2009

what kind of oil do you use.

Sometimes cheep oil doesn't make good oil pressure.

Cheap oil wouldnt have anything to do with it.. IF the oil was too thin it could do it, butttttttttt it already calls for 5w30 which is pretty thin, and its an 08 I wouldnt assume the bearings are worn much yet.. so I would guess the problem is something else.

Like posted previously, why isnt it at the GM dealer?

Cheep oil could have a lot to do with it...I have seen this quite a few times. I had a few customers come in complaining about the oil light on..we changed the oil out that they bought for 97 cents a liter at Walmart and the pressure issue stopped. Some oils are not API certified.

But yes I agree...bring it in for warranty.

hubob · October 13, 2009

what kind of oil do you use.

Sometimes cheep oil doesn't make good oil pressure.

Cheap oil wouldnt have anything to do with it.. IF the oil was too thin it could do it, butttttttttt it already calls for 5w30 which is pretty thin, and its an 08 I wouldnt assume the bearings are worn much yet.. so I would guess the problem is something else.

Like posted previously, why isnt it at the GM dealer?

Cheep oil could have a lot to do with it...I have seen this quite a few times. I had a few customers come in complaining about the oil light on..we changed the oil out that they bought for 97 cents a liter at Walmart and the pressure issue stopped. Some oils are not API certified.

But yes I agree...bring it in for warranty.

Cant do warranty cause the vin has been blocked by gm dealers to not do warranty work on it. The reason for this is cause it has a STS turbo system, Comp high performance, cam,lifters,and valve springs, performance tune, and also a 6inch suspension lift so with all that definitly voids the warranty. I took it in for transmission trouble and they would not do it under warranty so I had it rebuilt w/ high performance parts.

txab · October 13, 2009

Have you checked the pressure with another gauge?

Nytemare · October 13, 2009

You have your oil return pump set to high pressure, you should also hear a buzzer when the oil pressure drops. You need it in low mode when you are low in the rpm's. There should be a switch under the dash or in the ashtray....those are the usual install places for guys with the STS kit.

It takes its oil right off the ready tap beside the filter and "steels" oil pressure when you are at low rpm's...find the switch, its there somewhere.

Nytemare · October 17, 2009

How did everything work out??

hubob · October 17, 2009

How did everything work out??

still low oil pressure. the STS part wasnt doing it. Its something wrong internally cuz when the engine is cold which means the oil is thicker the pressure is just below 40psi but as it warms it drops lower and lower. So I believe we are going to pull the motor take out the cam,lifters,and valve springs and replace it w/ a 6.0L and install the cam and everything into it cuz the parts are interchangable. Plus the 6.0L will bolt right up to my tranny and all the connections are the same.

WilliamBos · October 18, 2009

How did everything work out??

still low oil pressure. the STS part wasnt doing it. Its something wrong internally cuz when the engine is cold which means the oil is thicker the pressure is just below 40psi but as it warms it drops lower and lower. So I believe we are going to pull the motor take out the cam,lifters,and valve springs and replace it w/ a 6.0L and install the cam and everything into it cuz the parts are interchangable. Plus the 6.0L will bolt right up to my tranny and all the connections are the same.

When you tear into the motor, please let us know what caused the low oil pressure.

Nytemare · October 18, 2009

Yeah....before you tear into it try running some 15W40 to see if the pressure is better...its not going to hurt anything if your tearing into it anyway.

Let me know...I am doing the STS on my truck and if its something that needs beefing up I would like to know. I may just build a 6.0L first and use that for the STS though. I was going to see if I could pick up an LQ9 for it or maybe even an LS6. Tear it apart, put some good aftermarket parts in there that will stand up to somewhere around the 2 bar mark, than I can run 14-18psi and not be worried.

desrtrat · October 19, 2009

also check your cam bearings. you may have one going bad. not uncommon

txab · October 19, 2009

Here's one of your posts in another thread.

I have an 08 Silverado w/ the 5.3L and w/ all the mods that have been done nothing can be fixed on it under warranty. Ive been having problems w/ oil pressure so I had a buddy of mine pull the heads off and see of he could find anything wrong and what he found is a deep groove in 2 or 3 cylinder walls and we are both pretty sure there is more things wrong internally. Not sure what would of caused this but the fact of the matter is the block needs replaced at least if not more..........

If you've got deep grooves in your cylinder walls then I'd be looking into cam, main and rod bearing clearances. That's what you need to do IMHO.