For some reason the last week or two when I start my truck up I have lots of oil pressure. After driving it for a bit (warms up) it goes down to ZERO at idle and when driving it goes up yo about 25 psi. Then for some reason it will go back to normal pressure at idle. When it goes to zero the dashboard beeps warning me "Loow Oil Pressure". I just changed my oil pressure sending unit today and the problem still exists. Its like the pressure goes up and down for no reason. I'm sure its not the stepper motor because I've changed every single one of them a few months ago. Does anybody have any ideas??? Its going to the dealer tomorrow morning. I'm scared to drive it at zero oil pressure even if its only at idle, I don't want to cause perminate damage. Any ideas fellas?

oh by the way, I also changed the oil and filter as well....

its not the stepper motor; because if it was the stepper motor the DIC wouldnt say "low oil pressure".

oil pump drive gear nut coming loose? Need to put a mechanical gauge on it to further diagnose this... I would not drive it though, seeing as you replaced the oil press sensor and it still goes to 0psi.

ben

Silly question but I'm going to ask, what grade of oil are you using?

I've been using castrol 15w-40 from day one. I LOVE my truck and the last think I want to do is damage it! Oh well, I'm off to the dealer to get ripped off now.

Did you get the sending unit from a dealer? If not, it may actually be a sending unit for a light. That would explain the 0 or 25 possibly. Unless you have an auxillary gauge, it is hard to determine if the reading that the dash is showing is accurate.

Backwards question, but is the oil level right. Low oil could create no pressure at idle and higher pressure at non idle.

Also, does it only loose pressure after it warms up? Or did it loose pressure after it warmed up the first time and now does it when cold?

ONLY looses pressure when warmed up, exactly. Oil pressure is high when cold. but the pressure doesn'y always drop when warm, just sometimes??? I put 12 quarts of oil every change sometimes a little more. I fill until the dip stick reads "full" and I check again when thr truck is warmed up as well.

I just hope its not the oil pump, that will cost me a bunch!

Just a thought but if the oil pump nut was loose I would sure think it would slip worse when its cold due the pump turning harder with the cold oil. I bet its electrical especially where is intermitant, the best way to tell is with a mechanical gauge that will alieviate any doubts.

that was my thought too. Its at the stealership now. Way too cold to work on it today without a garage. Oh well, guess I'll have to bring my checkbook with me when its finished...

Yeah let us know what they find please, Thanks Lee

Definately will do, thanks for all of the suggestions...

I put 12 quarts of oil every change sometimes a little more. I fill until the dip stick reads "full" and I check again when thr truck is warmed up as well.

Do you have an auxillary filter? 12 quarts is 2 quarts too much on a stock system.

10 qts is the stock fluid level.

OK well the dealership called and they have elimated everything except the DIC. They said everything else is fine and seem to think that there is a short in the DIC causing the guage to drop and the warning to display on the DIC. They put a mechanical oil pressure guage on the truck and waited for the oil pressure to fall then checked the mechanical guage and everything was OK. So it looks like I need a new DIC, they're charging me $360 for the part, who knows about the labor?

Shit man thats great news! Tell them you'll put the DIC in yourself, I would anyway. I dont think they are that bad to do.

it takes no time to put one in. I've already taken the old one out to replace stepper motors.

Yeah I was wondering where to buy those stepper motors? just for future referance in case I need to do that.

I put 12 quarts of oil every change sometimes a little more. I fill until the dip stick reads "full" and I check again when thr truck is warmed up as well.

Do you have an auxillary filter? 12 quarts is 2 quarts too much on a stock system.

10 qts is the stock fluid level.

Actually, 10.5 quarts is stock fluid level IIRC... but 12 quarts is definitely more than what's called for... and could create problems of its own...

Actually I quoted him. The quote mark didn't show up. Mine takes ten quarts exactly. tpitt

I got my stepper motors on eBay. Just search them on eBay.