My buddy just called me from florida and said he noticed a lower than normal oil presure reading at Idle ...He said it use to idle at or around 40 psi ...he has just noticed the presure to be around 20 psi .
Running he said the presure is normal .
I told him it is an electric gauge so it is not accurate ...Put a real gauge .
I told him to find out since the deal changed the oil if they put the right oil in the truck ...or even maybe they used a cheap oil .
He has 70,000 on the diesel ...He made an appointment at the dealer , but I don't think there going to do much but change the oil .
Any one have any ideas ..these engines are pretty bullet proof .
Thanks

Greg

 

On my 04 when the engine is cold it will be over 40 p.s.i. As the engine warms up the oil pressure goes down to a little over 10 at idle when fully warmed up. Nothing to major to worry about like you said it is electronic driven and won't get accurate unless with mechanical type, but what you described is normal operation.

 

the key here is really not the actual pressures. If the truck normally idles at at certain oil pressure at idle then that should be a benchmark. If all the sudden the pressure drops out of the normal range. You have a problem. Period. It may very well be the gauge, but you still have a problem and need to get the gauge looked at or get a good mechanical one.

You were right on the money when you said lower than normal. I know exactly how my truck acts normally, when it deviates drastically I find out whats wrong.

I got news for ya, if my truck EVER shows an INDICATED 10 psi, I'll be finding out what the hell is going on. It never drops below an indicated 40 psi.

 

Mine does this as well, cold it will be higher pressure, warms up lower pressure and everythings fine when driving. SOMETIMES even after its warmed up it will read higher but then same thing drops back down till I start going again.

 

276,986 miles on my truck and it drops down to a bit above 10 psi not ONE problem and I pull daily with it.

Oh and had to add doesnt leak anything and will only burn a little if I was a bit over on my oil changes otherwise if I change my oil every 5k it will stay full from beginning to end.

 

I understand and I completely agree with you. It does this predictably and consistantly right? It's a function of engine tolerances becoming greater with wear. BUT if tomorrow it dropped to HALF the psi it normally runs at, you can't tell me you wouldn't be wondering what just went wrong. If my vehicle over time with wear and tear gradually makes it's way down there, no problem. If it did it over night????? Um, something just bit the dust (probably spun a bearing).

The guy that this thread refers to said the truck normally idles at 40 psi and he "just noticed" that it's now at 20 under the same conditions. Something's going south with that gauge or motor, OR the guy is mistaken. sounds to me like it should be looked into further.

 

Tell him to get a real guage and tell us the pressures.

I see 75psi at cold startup. After warm, I see a tick under 25psi at idle and 65psi at 65mph. This is running 15w40 ChevDelo.

Factory guages suck.

 

calm down, this is normal for our trucks and the cummins engine. You will have two idle readings. You will have a cold idle reading, and you will have a warm idle reading.. Maybe the guy that started this thread has never paid attention to that.

 

OK I highly doubt something "just bit the dust" if his pressure is fine while driving and he seemed to just notice now that its different at idle. Now if he had posted all of a sudden while DRIVING the pressure dropped in half then I could see getting something looked at but at idle again doubt anything is wrong.

Also I think I have plenty of time and wear and tear and it hasnt changed or "gradually" made its way down there thats just how its been.

 

On a REAL gauge....

Cold Idle...>70psi
Hot Idle...~16-18psi
Idling after towing through the hills...~12-14psi As the engine cools down you can see the oil pressure come back up to 16-18psi.

Per the service manual....everything is OK, IF
>10psi at idle, >35psi at 2500rpm

I think DC has an oil switch at 7psi.

HTH

Tony

 

TonyB, what oil are you using?

 

rule is 10 psi for every 1000 rpm, so it still is with in the norms.

 

the gauge and sender are crappy. there was a post on here a few months back with erratic o/p readings, the member wisely quit using it and had it taken to the shop, they just changed out the sender and it was all fixed. the lube systems on the b's are 99.999999999999% reliable and bulletproof. more than likely a sender/gauge issue, and the real gauge like mentioned above will prove it, and peace of mind. even if it is a temp. installed gauge

 

where is the sender on these, and can you T off of the port to install an aftermarket gauge?

 

Valvoline 15W40

There is an 1/8" NPT pipe plug on top of the oil filter/cooler assy. Pull the plug & install a real gauge or the electric sending unit.

Tony