95 Grand Am rough running low oil pressure

oraclese

I'll try to explain this as best as I am able.

Vehicle history as of late:

95 Grand Am SE 3.1L V6 w/ ~280,000km (174,000 miles).

We just had the radiator, heater core, and intake gaskets replaced due to coolant leaks. Seems the coolant issue is all under control now.

Last oil change we went from conventional to synthetic. When I got the intake gaskets replaced, I believe he also did an oil change. No idea what type of oil (synthetic or conventional) he put in it, trying to find that out. I believe the oil filter was also changed. Just thought I'd mention this since this has to do with oil pressure.

Issue I'm currently having:

It's my fiance's car. She was driving home from work last night and she said the car was running very rough, bumpy in the engine. Almost died on her a couple times getting home. Once she got home, it stalled before she could shut the ignition off (I'm assuming this problem gets worse when it idles).

When this happened, she said the oil pressure gauge was almost bottoming out.

I checked the engine oil, and the transmission fluid for kicks (since we replaced the rad recently). They both look fine.

Seems that when you first star the car, the exhaust is really thick white. Just seems to be a lot of exhaust vs. other vehicles.

Any idea what is causing the rough running/low oil pressure? When I tried to start the vehicle this morning, it started and the oil pressure was fine, but lots of thick white exhaust at first, and it seemed to idle bumpy, started rough.

I'm sick of fixing this vehicle, but what do I expect with such high mileage?

burdawg

White smoke upon start up indicates coolant in one or more cylinders, and if it's bad enough it will run rough. Are you sure it's not gray smoke, which would indicate oil is leaking into the cylinders?
Check the coolant level.
When an engine is stalling or running very slow the oil pressure will be very low and I would expect the gauge to be bottoming out as you described.
It's not a good idea to switch a high mileage engine over to synthetic oil, it will lubricate OK, but will most likely leak out more than petroleum oil.
With that old of a Grand Am with those miles, you would have hard time convincing me it was worth repairing.

oraclese

The exhaust is white like you would see from a smoke machine.

I checked the coolant level last night, and it even seemed a little high (and some had been leaking through the resevoir cap, which is new, which leads me to think we put too much coolant in after the rad replacement).

And as far as I can tell, this vehicle doesn't leak a drop of oil. At least not on the ground.

I should also mention that the bleed valve for the coolant system was broken (at least it broke closed), so I can't effectively leak air out of the lines. Is there an alternative method of doing this? I plan to get the valve fixed if the new major issue can be resolved without breaking the bank (otherwise it's time to punt this car).

burdawg

I would do a pressure check on the cooling system to see if there's any leaks. If it won't hold pressure and you can't find any obvious leaks, then it likely confirms that coolant is leaking internally in the engine and is being output as steam when you start it. It doesn't take much leakage into a cylinder to make the steam, but it will only get worse. At worst it will hydrolock and you'll have a catastrophic failure like bent/broken rod for instance.
As far as the bleeder valve, without replacing it (I don't recall the valve on the older models) you can try finding the highest point in the cooling system that you can access like a hose or something and disconnect it to let out any trapped air. If it's like the bleeder on later models with a 3.4L then I believe you can just replace the entire valve (the base part) with a threaded plug.

needadvice3

MY CAR IDLING ROUGH AND STARTS SHAKING AT 40-45 AND 50-60 WHEN ACCELERATING. ALSO, CHECK ENGINE LIGHT JUST CAME ON. SOMEONE SAID IT MIGHT BE A CLOGGED FUEL FILTER. ANY INSIGHT?