Whats up guys, just bought my first car..94.. 3.4 and theres a lot of problems ive had to fix, and still more. In the past month the car has leaked oil, gas and transmision fluid. Fixed a rusty fuel injector, and changed 2 pressure lines going to and from the transmission; both fixes went well, problems solved. However my leaking oil repair has caused me a new problem.
Bought the car at 53 000 miles aware of 1 fix...it had a leaking oil pan. I replaced the oil pan which in turn created a new problem. The first time i started the car with its new oil pan, the oil light came on. I thought it obviously needed a little more oil since the pan had just been changed. I added more but the light didnt go away. Now the wierd thing about this is that, when i start the car when its been parked for say 30min or more, i get a for sure Low Oil light. But if i turn the car off and immediately start the car again, the Low Oil light disapears.

What i notice when i start driving is that i have good oil pressure in the beginning, it stays at halfway on the meter when im driving and close to halfway when i idle. But after maybe 15minutes the oil pressure decreases. Its fine when im over 20mph (just under the halfway mark), but when i come to a stop, the oil pressure goes pretty low, almost to the red.

Now what would cause this by a brand new oil pan having been just installed?
Why does the oil light come on, but dissapear if i turn the car off and immediatley on again?

Ive done a full oil change and put in the recomended oil type, and that did nothing. I read in another post where the guys camaro was having noticeable oil pressure fluctuations when he accelerated and a few of you suggested it could be the oil pump/oil pump bearings. It looks like im having a similar problem to his.

So any suggestions would be awesome.
Thnx

EDIT: The Low Oil light never came on before the new oil pan was installed.

 

Oil pressure increases as rpm's increase (when you accelerate). It decreases when you are not accelerating and the rpms are low. That is normal.

Maybe the sensor is sticky and when you did a complete tear down of the oil pan the sensor stuck or something (it happens to the coolant sensor often, I'm not sure if it's common w/ the oil sensor)

pete will know whats up

 

Check the oil level with the dipstick after the engine has been stopped for about 15-20 minutes, if the level is good then the oil level sensor is bad, or the wiring is bad. Do not use the oil level lite as a level indicator, use the dipstick to check the level. The light is there as a signal of last resort.

 

Those level sensors are made from an easy to damage material and the 'float' was probably damaged during the change. And turning the car off and restarting will turn the light off, that's normal. Follow Pete's advice.

Electric gauges are not your most accurate indicators of anything, unless you pay acordingly. You really need a mechanical gauge to check your problem and some engine specs from GM.

When you changed the pan, your oil pump probably lost it's prime (all the oil dained out of it) which is why your oil pressure light was on for a long time. During the pick up time, you might have damaged the pump or main bearings if you let it run too long without oil pressure.