1995 Z28, just got it and have been replacing parts due to previous owner not taking good care of the engine. Took it for a ride today to check it out and after about 2 miles the oil pressure fell to zero. Wasn't sure if it was reading correctly but pulled it into parking lot immediately. Could hear the valves clicking as I shut the engine off so I was sure that the oil pressure was reading correctly then. Now if I restart the engine the oil pressure seems to run fine for a few minutes then completely drop to zero at which point I shut engine off again to avoid damage. Since I am an extreme newbie to these cars could someone please tell me what these symptoms indicate is wrong. Of course we will take a look at the oil pump tomorrow but is there any other thing that would cause it to act like this? What does an oil sending unit do? Could an oil sending unit cause this irratic behavior? What do I check first? Thanks for any and all replies to this thread.

Eddie

 

anyone?

 

The sending unit just reads the pressure and sends it to the gauge. With what you are describing it sounds like time for a new oil pump. I have never done one on an LT1, but it usually involves pulling the engine on most cars. do a search on the board for oil pump replacement, I am sure you'll find some info. Good luck with the car, sounds like a tough break.

Ed

 

u gotta pull the oil pan to get to the pump and it is a bitch and a ***en half to take the oil pan off when the motor is in the engine. i would highly recomend u pull the engine. i replaced the oil pan gasket when i changed the clutch and it was a bitch and a half, and i used a lift and everything. good luck!!!

 

I wouldnt take any chances untill you are 100% sure what the problem is. You may have just saved your motor by turning it off. I mean it could be somthing simple and nothing big. But dont take the chance or messing anything up.

 

hmmm, this is a tough one, cuz if it was the pump it would just fail... not run for 5 mins, and fail...

but u said u can hear the ticking and stuff as well... hmmm

my gauge is messed up, so it reads 80 all the time, and i hope i'm not running on low oil pres... cuz that would suck... i gotta change that thing asap lol...

gl with w/e it is.... only thing i can think that would cause this is the oil pump tho....

 

when my pickup fell off it did the exact same thing- only 20 psi static- but i ran thicker oil b/c i knew what was up for 2 days (20 miles)

 

yes i did hear ticking just as i was about to shut off the engine. sounded like valves clicking from no oil making it up top, hopefully it didnt do any serious damage. Still dont understand why the pressure would come back when I restarted it a couple of minutes later.

Eddie

 

If your gauge is maxed out all the time, the wire to the sending unit could merely be off or open.

95 z28 noob:
It might be a good idea to put a mechanical oil pressure gauge on it for testing purposes. You might also drain the oil, drop the filter and look for the presence of any metal.

 

be off or open? ehhh?

 

good idea, oil was just put in today so if any metal i got major problems. thanks to all for the advice, i am fearing the worse but hoping for the best.

Eddie

 

I had the same problem a few months ago when I first picked up my car and I was driving it home. What it turned out to be was a freak coincidence of two things going wrong at once. I was leaking oil from some blown gaskets that I didn't see (oil pan, timing cover) so the pressure was going down but the gauge didn't read it until I was on about 2 quarts, then the oil pump broke. It's a pain in the a$$ to replace both. For the oil pump you have to disconnect the starter, exhaust, motor mounts, and drop the front clip to remove the pan. The timing cover is no better. I'd reccomend having an experienced person do those.

 

Wire connector off (unplugged from) the sensor or wire broken (open circuit).

 

Checked the sensor, once off pressure guage went full. Dropped the oil and filter. Appeared to be lots of metal in there. Thinking it may be done for. We are gonna replace the oil pump anyway as it did appear that little if any oil was making it to the top. This is the last thing before actually opening the engine up and going in deep. If the engine does have to be completely redone...............about how much to bring it to a 383?? hehehehe, why not if we are gonna already be in there!

Thanks again for all the help,
Eddie

 

Oil pump removed late today........replacement oil pump came in right at quitting time so its on the agenda for tomorrow. However, the metal in the oil has me a bit worried. If the better oil flow to the top doesnt show up clean (no metal) oil after a short run then I guess its off to the rebuilding crap. Bummer, I was hoping to milk 20,000 + miles out of this thing before having to go deep in the engine. Oh well, life's a b*tch!

Thanks again for all the suggestions,
Eddie