Oil Pressure Problem!!!
 

Here it goes. Whenever i forst start my car my oil pressure readings are normal. After I drive it for about 20 minutes, everytime i stop and let the car idle the oil pressure bounces from 0 back to normal. Then whenever i raise the rpm's...the oil pressure stays up. What could be my problem????

It might just be your sender. I know ive talked to a few people who have had them go bad on them. That would be my first try.

i havent looked at mine in a while but i think that you can hit it with a little sandpaper and clean it . what kind of oil filter do you use?

Re: Oil Pressure Problem!!!
 

Mine is the same way. Is it stock? It just sits there at 0 when I'm at a stop/idle.. then when I start driving it raises again.

I thought maybe it was just the shitty gauge. I know I've changed the sending unit a few years ago.

What do you do with the sandpaper?

I use a Canadian tire formula 1 filter. Im assuming you would use the sandpaper to clean the contact where the wire goes to the sending unit. Sometimes the unit itself will start to read wrong. The only other possibility is if its only doing it when the engine is idling then you may really have low oil pressure and its just not reading much so it goes down to 0. What does it go to when you bring the rpms up. Usually you should check the oil pressure at about 2000 but it should never be below about 7psi

My first guess was the sending unit also. I just installed a high volume oil pump about 100 miles ago and didnt change out the sending unit. the rpm's go up as the throttle goes up. Around 2000 rpm's it goes up to the middle notch (im guessing around 50 or 60?) but it wont go up above that too much. Thanx for all the help!

Well my first thought would be too hook a mechanical gauge up to where the sending unit screws into the block and see what your pressure is. I just went through this with my 95 GTS and was hoping it was just the sending unit only to find out that it was not that but the fact that I have 164,000 very hard miles on the motor and the main bearings are pretty much shot. Best of luck to you.

Low oil pressure means excessive clearence between the bearings and crank. When the motor heats up the clearence expands and the oil viscosity drops. This is not a good thing.

As for the gauge, there is a diaphram and a spring, the oil pressure forces the diaphram back this gives the voltage reading which is converted to PSI (sort of) The sender unit can get crapped up internally and give erratic readings.

Bouncing readings sound like a crappy sender to me, get a new one on there first.

The stock gauge is pretty good actually, most dont want to face the fact the engine needs a rebuild!!

My car reads 70 - 75 PSI cold. 50-55 psi while driving hot, 10- 20 psi at idle ( Very bottom of N) so I know the bearings are getting kinda thin at 150,000 miles.

My beat up 305 in my Chevy has a reground crank and new bearings and oil pump. Even when fully hot still gets over 40 psi idling in drive.