Low oil level AND oil pressure light

**davidw** · 10-25-2011

Just did a motor swap after my wife's 2003 Grand Prix GT died with 170k on it. The new motor starts and runs fine with no unusual noises. The oil pressure light will come on after 15-30 seconds of running and then later the oil level light will come on. It does have oil and it is getting oil to the rockers. All sensors are hooked up. Is there any way to test the sending unit or maybe even the tan and black wires that come off of it? Could I have pinched a wire or two and that be causing the problem? Any help is appreciated!

**FordMan77** · 10-25-2011

Could be a bad pressure sensor. And the low oil level sensor is in the front of the pan and those wires are easily cut when installing a new motor. Not sure how to test the pressure sensor. That is a normally open circuit IIRC. It only closes when you have about 5psi, which is usually too late.

If that fails I would get a true oil pressure gauge on there right away just to be sure the pressure really is what its supposed to be. Just install the sending unit where the stock sensor is and see what you get.

**BillBoost37** · 10-26-2011

I'd be concerned. If oil return was blocked, that could cause the symptoms. Sure it woudl run fine for a while as it probably gets oil returned slowly.. but yeah.

I'd fire it up with a mechanical oil pressure gauge on it. That tells you w/o any doubts if your light is incorrect. Then watching that, I'd check the oil level when it's running. I know this shouldn't give a good reading as oil should be flying everywhere. But if the dipstick comes back dry..you know there's an oil return issue.

**davidw** · 10-26-2011

Thankds for the help guys, It is going to sit till I can get a gauge on it. It is just strange that it comes on after running for a bit. It hasn't been driven or eveb ran for anytime once the light came on. Any other ideas out there?

**davidw** · 10-26-2011

When I first started it one of the coolant Elvis wasn't completely seated and got the oil pressure sensor wet, could that be effecting things?

**BillBoost37** · 10-26-2011

It shouldn't. All our conectors should ahve a rubber seal on them.

Is your rubber seal in place? Are your wires good?

The level sensor is totally seperate from the pressure sensor. Which is why when you said low pressure then the low level happens. That would point the pan being drained of oil. Which asks the question of where did it go... which is only answered by .. stored somewhere in the engine. Which leads me back to some clogged oil return. which is very uncommon and has only happened with improper head gasket install etc from what I've seen.

**davidw** · 10-26-2011

Only gaskets changed were upper and lower intake (cause it was out and easier to do) and oil pan gasket. I did pull the oil filter housing by am certain that he spring went in first then the little metal cup.