I am having this problem, thats is why i found these forums.I just bought the car for $2200 its a 1995 w/ 125k it'* a florida car and there is nothing wrong with execpt the Low oil pressure after the car heats up. but as soon as i step on the gas it goes back up to 40 psi. there is no pinging or knockin, no smoke out the tail pipe. The car runs fine! Also i would like to note, The U.I.M. was just done. Along with all the vacuum lines, before i bought it. it also has a slight oil leak. im not sure where it is, i plan on adding some die to and buying a black light. also i average 27mpg

P.*.
I love this car. It is one of the best cars i have ever bought. I know its a 1995, but this thing is ROCK SOLID and i would drive this car to cali if i had to. So long as this oil pressure problem is nothign serious.

Here is a picture of the car started. it is 96°F out side.


Here is the oil pressure as i accel


Here is the oil pressure when i come to a complete stop after running the car for 10-15 mins.

That looks like a terrific car for what you paid for it. I wish I could find a deal like that.
I am curious to know what is causing the oil psi to drop at temperture. There is at least one other thread about this and so far we haven't got a definitive answer.
My educated guess is that it is worn engine bearings. Could be rod bearings, could be cam bearings, I don't know which would be more likely.

It is obvious the the oil is thinning enough when it gets hot to make the pressure drop.
Do you know whether it has synthetic oil in it? Maybe a heavy weight oil would eleviate the problem for the time being. I say you have nothing to loose by trying that.
I don't think the sending unit is at fault, since the psi changes are consistant.

What part of the country are you in?

Do you know what weight oil is in the engine?

Could be a bad oil sensor. Check the plugs for corrosion and clean them up. See if that helps any.

Thanks Thin Indian! The guy i got the car from was a ASE certified mechanic and had the car for 10 years. It was his wife'*.. She barley drove as you can tell! it only has 125k also. Thats almost under 9500k a year!

as for the oil he was running synthetic and i just had the oil changed yesterday to 5w30.

I live in Tampa, Floida

Wow. If that was my car and I was having the exact problem with the oil psi, I would have put at least 10w40, probably 20w50, knowing summer is coming.
Was the pressure dropping before you changed the oil?

Maybe you should change it back out, and capture the drained new oil to put back in next November.

Yes it was but to my defense i thought it was normal?.. But for some reason my brain told me to google it and thats where this post comes from.. I am new to florida.. and the climate.. I have always ran 5w30 in all my cars. Also to my defense I took it to midas. You think they would have asked me or suggested it?

Should i take it back and complain?

I have a '96 Bonneville SE and have the exact same problem, but ever since I got the car a year ago I have used 5w30 and about a month ago it started having the same problem. My car is going in the shop on thursday and I'm hoping they can get it figured out. You got that car for a great price. I paid $3,000 for mine and it had 82K miles on it and worked beautifully.

Do you mean next thursday? Also how is your car acting? does it run fine? Because my car Runs fine? it does not have any white smoke..black smoke..Pings..Knocks, not one sign that its affecting some thing?

Yeah, next thursday, My car runs fine besides the Air Conditioner being broken everything else works fine. Nothing weird coming out the exhaust pipe. I got my water pump and belt and belt tensioner replaced a couple months, but from then on things have been great.

Ok so since every one keeps talking about coolant and the color. Monday when i found out that the oil pressure was fluctuating, i got scared and went and marked the reserve/overflow with a marker. i have been checking it on the regular and have not seen any differnce'*. but when i woke up this morning..

Can you see my mark and how much it has gone down?



He is what it looks like in side the reserve/overflow tank. it does not even look like coolant?? look'* like water and oil? does not look like coolant and oil to me



Here is what my Coolant look'* like in the radiator






I also would like to note, Prior to buying this car. The guy told me the U.I.M. Was replaced because of it failing. Could any of this have to do with why my oil pressure fluctuate'*?