I put a new oil pressure sending unit thing (the black tube-like think that screws into the engine right above the oil filter) on a couple weeks ago because the old one began leaking oil right out the front. I got a great pressure reading for about a week, but now it's back down, lower than it was initially with the bad unit. It's to the point where the oil pressure gauge barely stays above zero, but is still in the red. Sometimes it looks like it doesn't even move when I start it after it's been running. It's never been this low. I checked for a leak, but didn't find any, and I'm not low. It's time for an oil change, and every time it's changed it always brings the pressure back up over half for about 2000 miles. I'm going to change it tomorrow before I drive it again and see if it helps. Could it just be the sending unit to the gauge? I'm praying it's not the oil pump, but that's probably a strong possibility. Oh, and what oil do you guys recommend? It's a 3.8 with 217xxx miles.

 

oil pumps DO NOT create pressure.Try hooking up a manual pressure gauge and seeing what the pressure is at.You could have a clogged oil pickup blocking the flow of oil.You may want to try running a heavier weight oil especially with the miles on you car and summer approaching

 

the oil pump on the 3.8 is a lil weird... its kinda built into the motor. I had an issue with the oil pressure valve getting stuck and blowing out my oil filter seal. I WAS going to rebuild the oil pump... till I saw how much further into the engine I was going to have to go. I would look at the design and decide if that the route ya wanna take before ya start taking things apart.

 

the oil pump doesn't create pressure? i'll remember that. anyway, if it's a clogged pickup, what kind of work would i be getting into? well, what kind of work would i be paying for? lol

 

oh, and how thick of oil should i use?

 

Ok I'll bit, what does create oil pressure?

 

it doesn't? hmmmm.... if that pressure relief valve that is part of the oil pump system gets stuck, it creates enuf pressure to blow the oil filter seal... then it dumps 5 quarts of oil in your driveway (trust me... seen it first hand twice)

 

i changed the sending unit that sends the pressure to the gauge, and it's fine now. that's the third unit i've put on in 2 weeks, hopefully it's just a coincidence that the other two messed up and not something serious with my car.

 

bearing,clearances between the bearings.If oil pumps created pressure then all you would have to do is put a new oil pump as your engine got worn out with high miles.Ive seen people immediately put a new oil pump on because of low oil pressure.A spun bearing can create oil pressure problems.Oil pumps let oil flow but they dont create the pressure.

 

Ali, you're thinking backwards here. The oil pump creates the pressure. Tight bearing tolerances creates the back-pressure, and therefore the pressure readings on your gauge.
If an oil pump's output remained the same throughout it's life, oil pressure drop would be caused by worn bearings due to them not being able to hold as much oil back from having sloppier tolerances (more clearance).
And I say "if", because oil pumps can wear and drop pressure as well.