Oil pressure issues
06-20-2010, 05:11 PM
#1
Thread Starter
Join Date: May 2010
Location: St. Clair Shores, MI
Posts: 41
Oil pressure issues
Hey guys,
I hope i dont have an issue but wanted a second look at it. Its a 90 5.0...
So I start it up and everything is fine, I drive around for about 20 minutes and all is still good. Little bit after that when I get to a light and the RPM's go down to about 900 the oil pressure just drops to nothing. I give it a little gas to about 1500 RPM's and it goes back up but then drops at idle again. Now if i keep driving it and get to a light then it has to get up to 1700 RPM's at the light before it goes up. While I am driving it has oil pressure the whole time and no problems. Stock oil gauge.
Oil sender bad?
Oil pump bad?
Other than buying a new guage is there a way to check the pressure? thanks everyone!
I hope i dont have an issue but wanted a second look at it. Its a 90 5.0...
So I start it up and everything is fine, I drive around for about 20 minutes and all is still good. Little bit after that when I get to a light and the RPM's go down to about 900 the oil pressure just drops to nothing. I give it a little gas to about 1500 RPM's and it goes back up but then drops at idle again. Now if i keep driving it and get to a light then it has to get up to 1700 RPM's at the light before it goes up. While I am driving it has oil pressure the whole time and no problems. Stock oil gauge.
Oil sender bad?
Oil pump bad?
Other than buying a new guage is there a way to check the pressure? thanks everyone!
06-20-2010, 08:57 PM
#3
4th Gear Member
Join Date: Apr 2009
Location: N.C.
Posts: 1,893
Ground sending unit wire turn ignition on. Gauge should go all the way up. Do not let it peg. Try a sending unit. If does not do as earlier described is gauge problem. Hook up mechanical gauge to know what oil pressure really is doing. Bubba
06-26-2010, 11:23 PM
#5
Join Date: Feb 2009
Location: PA
Posts: 2
Ok I have a question on this too. I also have a 90GT. But I have the same problem to the T. I have a mechanical guage but it reads the same thing. Once the engine warms up the pressure goes down and stays down until you start driving it. Now it has pressure when you drive it but when you give it gas it starts to go down a little bit. Sorry to just jump in but i didn't want to start a new one if there was already one going for this problem.
06-27-2010, 07:19 AM
#6
Join Date: Sep 2009
Location: ny
Posts: 33
^ your issues could be in the bearings, more than likely cam bearings but it is nearly impossible to diagnose from here. I had an identical problem with a sbc engine that is what I'm basing this guess on. Hows the oil? last change, brand, etc. I would put a filter magnet on the oil filter and run it for a day then drop the oil and open it up see whats in there.
06-28-2010, 10:48 AM
#8
Join Date: Feb 2009
Location: PA
Posts: 2
Well I run synthetic in castrol and i changed it maybe 1500 miles ago and rebuilt the motor about 3000 miles ago. I had to change the main bearing after i rebuilt it because i had the wrong ones so i bought a whole new bottom end. I even put a new oil pump on it. I believe it was the high output one. But it does burn oil and leak some I don't drive it that much cause i don't wanna blow the motor. It seems to do better when i fill the oil up beyond the fill mark. Thanks for helping out and throwing some ideas around.
06-29-2010, 08:31 AM
#9
1st Gear Member
Join Date: Jan 2010
Location: georgia
Posts: 86
Oil pressure drops as oil warms up and thins out, that's normal. You should have at least 10lbs at idle and at least 10lbs per 1,000rpm(ie, 20lbs and 2,000, 30lbs at 3,000 etc).
I don't know if this will help you, but I was having gauge problems. This was how the gauge reading was explained to me. For the one who wanted to know where it should be.
I don't know if this will help you, but I was having gauge problems. This was how the gauge reading was explained to me. For the one who wanted to know where it should be.
