interesting oil pressure issue...

[4xcrazy]

This is in an '05 Avalanche, 5.3 engine, running full synthetic 10/30. idles and runs all day with the oil pressure gauge reading 80psi, all the time, which i think is kinda weird,,, unless you hit the throttle real hard, like say if you want to get going in a pretty good rush, or passing pretty quickly, when the motor rev's up in the higher range, the oil pressure will just drop, almost acts like it's low on oil, and loses pick up...

I just checked the oil level, it's full, still looks clean,to a certain point,,i was told this motor takes about 7qts of oil.

If you hold the motor at that higher rpm for too long, which i did yesterday, the gauge drops and the dinger bell rang at me telling me there was low oil pressure.


Any ideas on this??

 

[Big Ray]

What I would do: Verify oil pressure with a mechanical gauge...I'm thinking you have a bad sending unit.

 

[496truck]

The guage clusters on those trucks have issues. They will have anything from odd guage readings to false speedo readings. My friends truck would say 80 at 40ish actual mph and finally went right up to 120 and stayed there for weeks, the other guages read sporatically when they felt like it.

 

[79bonanza]

'05 Avalanche hold 6 quarts of oil. all gm trucks with v8's in them hold 6 quarts except for the 350 trucks from the 90's and stuff.

 

[496truck]

Except the 8.1. That thing took at least 7 qts. Not applicable to this particular problem but a blanket statement like "all GM trucks with V8s" is incorrect.

 

[Fordum]

Verify with a known good gauge.

If it is really doing that, then I would suspect the pickup tube on the oil pump is cracked or loose.
Drawing in a good chunk of its oil from just under the surface and sucks air when you increase the volume.

But, 80psi is not likely, so I suspect a gauge problem.

 

[79bonanza]

ok my bad all newer v8 gm trucks besides the 8.1 and the duramax hold 6 quarts. i left those two out because i didnt figure he had a 8.1 or a duramax in his truck therefor it wasent relevent and just extra info.

 

[4xcrazy]

i took video of this thing doiong it, I haven't been able to cross my eyes fast enough yet to watch to see exactly where the tach is when the oil pressure starts to drop, mainly cause i'm driving at the same time, paying attention, watching the oil pressure gauge, because when it does hit the higher rpm's it starts to drop real quick.

I haven't heard any knocking of any type or engine clatter or anything when it does, but i will be checking soon with a seperate gauge to verify any change in actual oil pressure.

I know about the gauge cluster problems before, and i know this one has been changed out already. This is Allans truck, (Justhorsinarownd) I have been in town for awhile helping Jenn get moved into a new place and other things with my family, but when i saw what the gauge was doing, it concerned me, as i don't want her to get stuck out somewhere because of an possible oil problem.

Working on getting the video loaded up and i'll post it as soon as i can so you can actually see what it does.

 

[jt512]

Our company has 2 Chevys with 6.0's, both of which I have had to replace sending units on, easy enough to do, kind of a pain to get to. One would read high pressure 80psi and up, the other ,one day started reading super low all of a sudden. Sending units fixed both. One of the 2 also had lots of cluster issues, ended up sending the cluster out to a company we found through eBay, somewhere in MA, they went through it all and shipped it back for less the $200, it's been working perfect ever since ( about 18-20 months ago).


Forgot to mention both are 2500 hd's , an 03 and a 04.

 

[DokWatson]

If you actually had 80psi at idle, and revved it...something would have popped by now. Probably a bad sender, gauge is most likely fine.

 

[4xcrazy]

http://www.youtube.com/watch?v=C5renCouH0E

here's the link since i don't care how to learn how to mess around with embedding vids..

if i were to keep on the throttle hard like that, it would and has already dropped into the red and sounded the warning bell at me.

 

[Fordum]

You need gas.........

I'm betting its a sending unit. But, I would not be willing to bet an engine. Check it with another gauge as soon as you can.

 

[4xcrazy]

You need gas.........

I'm betting its a sending unit. But, I would not be willing to bet an engine. Check it with another gauge as soon as you can.

LOL, this truck ALWAYS needs gas i complain to her about it all the time, she says it's against natural law for women to put gas in a vehicle though.

 

[tRustyK5]

I agree that it's likely a sender. I don't believe 80 psi for a minute.

Does the gauge do the same if the truck is in park or neutral and you hit those rpm's? I'm thinking under load the engine is torquing over and maybe pinching a wire or something...

I'd install a cheap mechanical gauge and see what is really going on.

Rene

 

[4xcrazy]

I agree that it's likely a sender. I don't believe 80 psi for a minute.

Does the gauge do the same if the truck is in park or neutral and you hit those rpm's? I'm thinking under load the engine is torquing over and maybe pinching a wire or something...

I'd install a cheap mechanical gauge and see what is really going on.

Rene

didn't even think to try this, i'll let you know here in a bit...

 

[4xcrazy]

I agree that it's likely a sender. I don't believe 80 psi for a minute.

Does the gauge do the same if the truck is in park or neutral and you hit those rpm's? I'm thinking under load the engine is torquing over and maybe pinching a wire or something...

I'd install a cheap mechanical gauge and see what is really going on.

Rene

yup, checked it yesterday when i went out to pick people up, rev'd it, and tried to watch the rpm's when the gauge started falling, right near the 4000 mark. Gonna swap out the sender for a new one hopefully, as i also agree that a constant 80 psi can't be right either, then go from there.