so my car will start up and idle, well barely idle, but the problem is is that my oil pressure is like 15-20 on the gauge, and was wondering what might be the problem?

it has a high volume oil pump in it, brand new, so any ideas would be greatly appreciated.

-jeremy

 

i got the same probwit the oil but mines the original 130,000 and i get like 15-20 psi at idle when cold and 5psi at idle when its warmed up.... it could be ur gauge/sender... get a mechanical gauge be they are more accurate just to check the pressure when running, u could have bad bearings which would cause bad pressure which means ripping the engine out and putting in new bearings etc

 

if its 15-20 psi when its warm at idle it should be fine

 

I know if your car is idleing really low your oil pressure will be low. If you idle it up it should go up.

 

my oil pressure guage stays at 15 psi, i rev it.. it doesnt go up.. it doesnt go down.. nothing changes when the car starts, i replaced the sender, and its still showing 15 on the guage..

I talked to my friend who installed the oil pan, and he thinks that maybe the pickup on the oil pump might be too tall, and be bottoming out on the oil pan which may be causing the problem.. does that sound possible?

if that aint the problem what could it be?

 

if the pick up wasnt getting enough oil at speed your oil pressure would drop

does the gauge move at startup at all?

 

my oil pressure rises from 0 to 15, and stays at a steady 15, it doesnt change no matter what, i rev it stays the same, nothing happens, and im thinking that if its having a hard time pulling the oil in, like from the pickup touching the bottom of the pan, then it might show up low like that.. but not sure.

 

Since you've already searched and found the HUNDREDS of posts about "my oil pressure gauge reads low/high/erratic/weird/whatever" and found that the cause is either a blown-up motor (expensive, hard to fix, takes a whole day even sometimes) or the oil pressure gauge sending unit (cheep, easy, takes about 3 minutes to fix if you stop for a cold one along the way), what happened when you replaced the oil pressure sending unit?

 

yes.. ive been looking for days, through hundreds of posts on many forums, trying to figure out what my oil pressure problem is, i replace the sending unit like i stated above and it still reads the same.

someone recommended buying a mechanical oil pressure guage, well ill buy one as soon as i can.. but i do think my guage is accurate and i am really only getting 15 psi, im just trying to figure out if its possible if my pickup on my oil pump is too long, if that could cause a problem before i spend hours trying to take my stupid oil pan off..

yes there is a possibility of my engine needing rebuild or whatever.. but ya know what, im trying to figure out what it is before i try that route, so before coming in here and assuming that i havent read around, think again.. so unless you have any real input on my problem... please dont act like im stupid.

my theory is that my oil pump pickup is bottoming out on my oilpan which is restricting the flow on the pump, which could cause it to not get any higher than 15 psi, so my question is.. does that sound possible? the reason i think it bottoms out is because my pump and pickup are for a truck 350 for a deeper oil pan...

 

So if you replaced the OPSU and the gauge still reads wrong, odds are, you have a genuine oil pressure problem. You can try the mech gauge thing; but somehow I doubt it will tell you anything you don't already know. The gauge in the dash hardly ever goes bad.

These engines do not need a high-volume oil pump. They cause more problems (any) than they solve (none). The best setup is either the replacement for the stock pump, which is a Melling M55A with a 55S screen and a IS-55E drive shaft; or, a standard M55 pump with a Mr Gasket 26 spring installed (costs less to do it that way, results are about the same), and the same screen and shaft part #s.

Furthermore, the oil pumps in these engines (Chevy V8s) ALMOST NEVER "go bad" or otherwise need replacement. If you have an old motor and it had oil pressure problems, and that's why the pump got replaced, then the motor still has whatever problem it had that caused the pressure to be low in the first place, which was almost certainly NOT the pump. Most often it's caused by excessive clearance in the crankshaft bearings, either the mains or the rods or both. A "rebuild" might not be necessary to fix that though, although most often it is. Simply replacing the crank and bearings ("crank kit") will generally get the pressure back. On the other hand, if the engine is either so worn out from use or has been so poorly maintained in its past or whatever, to the point that the bearings are worn out, then the rest of it probably isn't in real good shape either; and just getting the oil pressure back to normal won't restore it to "like new" condition. On the other hand, if it's a recently rebuilt motor and it's just going through the infantile failure and debugging process, then maybe it's a different matter.

It is possible that the pickup is too close to the pan; that would definitely cause a restriction in the system, which would in turn lead to low oil pressure. Add the difficulty in getting this measurement right, to the long list of good reasons NOT TO do this job laying under the car; but rather, to pull the motor and turn it upside down. Among those reasons is, that it takes less time to pull it than to lay on the ground.

Why was the pump replaced? What was the pressure with the old pump? What kind of condition overall is the motor in?

 

the motor is used, and i was told that it is in good running order, i bought this from another car, the oil pan was dented and the old pump was a little beat up, so i replaced it with a new pump that my friend had for his truck, i can't really tell you off had of the motor had oil problems before, but even if it were bearing issues, wouldnt the pressure go up with the rpms?

the rpms are steady, a solid 15psi, it doesnt move besides when i start the car up, it goes up stays at 15, but thats it, even if the car warms up, its stays the same, doesnt go down.. so thats why i started thinking that maybe its the pickup...

I would much rather not pull the engine out again, but if i have to...

 

I know that this is stupid and you have probably already checked, but is the oil at the proper level? Sometimes if there is not enough oil, the pressure won't change when you rev it, because there isn't enough oil to make the pressure.

It would have to be really low, but I thought I would mention it.