sudden drop in oil pressure??? what could cause this

90lxcoupe

Dirt-Old 20+Year Member
Oct 7, 2003
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ok i just got my car back on the road today and i took it to a local cruise night and it was running great, no problems at all. when i left there i went to my buddys house and romped on it throught first and second gear and the next time i looked at my oil pressure it was down to about 35 to 40 and when i was driving it was around 60. but before that it was at a little ove 50 at idle and a little over 75 when i was cruising around. what could cause this problem?? if it helps this is the first time ive driven the car more than just around the block since i put the supercharger on it and i've been trying to keep the rpms below 5300
 
One possibility is you oil sender unit is starting to go bad....a similar thing happened to me. I would be driving and the oil pressure seemed fine, then when I was at a stop and the car was idling, the guage would slowly drop in pressure all the way to 0.....stressful, I tell ya I ended up replacing the sender and it turned out it was the problem.
 
Have you driven it just like this before (same amount of time, same conditions, etc)?

Otherwise, I am with Jaackal. Between a romp, warmer temps (vs winter) and a blower, you can heat the oil up a bit.

Good luck.
 

had the same probelm i would sit at a light when idling and the oil pressure guage would dancing up and down, change dthe oil pressure sending with and ran new wire and see was back to normal.
 
I paid close attention to my car today and when I started it this morning it idles at about 60 psi and it climbed to about 64 psi at 3000rpm. Once it was warm it settled to about 50-52 psi. When I got off the expressway it idled at about 40 psi. Those are pretty normal. Nothing to worry about IMO.

I have a mechanical gauge BTW.
 
My car would go to zero everytime I would get on it after I rebuilt the motor....scared the crap out of me....then found out the wire that goes onto the send unit was a little loose and wouldn't make contact all the time