mholland08

Hey guys i have a 96 Z28 with 83,000 miles on it and on start up the oil pressure reads fine when it is cold but after it warms up at idle it drops to around 10psi and in gear drops to 0psi and check gauges and service engine light turn on. When i accelerate the oil pressure jumps back up. Took it into the mechanic and he put a new sending unit in and tested it with a manual gauge and it read normal and was fine right away for a couple days and now it is doing the same thing, motor still has tons of power and has no noises or power loss of any sort. Just wondering what approach i should take next? Is it the gauge itself that is shot? weak oil pump? i wouldnt think the main bearings would be worn because i rarely drive it and it has always been taken very good care of? just looking for some answers! thanks

leadfoot4

iTrader: (1)

What are you using for oil, I mean what weight?

englundjd

it could be that the sending unit he installed was just a bad unit.

what is your oil pressure at idle according to the mechanics guage?
technicly 10psi is ok, but much lower then that and your probably asking for problems

mholland08

using 5W-30 and at idle oil pressure is at 8-10psi on mechanics gauge, it runs at 10 psi at idle on stock gauge but after it warms up it drops to 0psi and check gauges light comes on and service engine light is on because of that, but when its at 0psi it sounds perfect at idle not wanting to die at all or missing at all. same goes for when im driving if i slow down for a stop light it will drop down to 0psi and climb back as soon as i accelerate

mholland08

thinking possibly a bad gauge? could it be anything else? if it was a oil pump issue or main bearings wouldnt i notice a loss of power or it trying to die at idle when its at 0psi?

ramair 1

iTrader: (2)

i would think if you really had no oil pressure there would be some lifter or other noises coming from that motor

mholland08

yea i thought there would be some kind of noise or missing or something, the motor has been well maintained from previous owner and myself and has not had any hard miles on it, basically a poker run car and cruiser every once in awhile, sits in the warm garage all winter, not like it is getting driven hard so thats why im not sure it is anything major, but you never know i guess

mholland08

probably going to take it in this week and have a new gauge installed and see if that does the trick, if not then i dont really know what to do besides have him check out the mains and oil pump?!?!

blackjack325

iTrader: (1)

Had this issue when i bought my car from the previous owner. Turned out, for me, that it really was low oil pressure. Shot crank and cam bearings.

Issue, we found, was previous owner had put a high volume pump on the stock volume oil pan. Currently running well but with the car warm at idle sits between low (red line) and the first line. Not sure what PSI that is. But when i get on the brakes hard the oil pressure drops to zero, then back between to that spot.

Now i gotta figure out why it does that.