Mechanics

OIL PRESSURE GAUGE

Pontiac Bonneville

Pontiac Bonneville 1996 154,000 original miles, 500 on rebuilt engine.

I recently had my engine and manifold intake replaced. I also had the oil level indicator replaced. About a week or so ago, I noticed that the oil pressure was low. Then when I turned a corner the needle went all the way down to zero. It also acts as if it going to shut off when I start it unless I promptly hit the gas pedal. There is also a cloud of white smoke at startup. I took the car back to the mechanic who installed everything and was told that the oil was fine and didn't find anything wrong. Also said that dash reading was wrong. I don't know if there is a problem with the oil or engine and if something is wrong I want the person I paid $1000 to fix the problem. Could you give an idea of what the problem may be.
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Tamwa24
March 2, 2007.



White smoke would indicate coolant in the combustion chamber (could be the intake manifold).

Check the oil level and make sure it is full. Have the cooling system pressure tested for leaks.

If coolant is present in the combustion chamber it will always fry your O2 sensor.

If coolant is present in the oil it will very quickly strip the oil film off the bearings causing a knock.

As far as the oil level, there are baffles in the pan to prevent oil starvation during hard turns. Only thing I could think of is a low oil level or a bad sensor.

If you see coolant in the oil (brown milky color) do not drive/start the car.

Did you mean oil level (low oil warning) or oil pressure?

Tiny
Mmprince3000
Mar 2, 2007.
Well my husbandand I checked the oil yesterday and didn't see any on the indicator stick. I took the car back to the mechanic that fixed it and he told me that it was only a quart low. There is also a whistling noise when the oil indicator stick is pulled out while the engine is running, almost like there's a suction there. Also, when the oil cap is removed while the engine is running, the engine shuts off. Yesterday a strange noise (sounded like clicking ) started when the car is accelerated. It was the oil pressure that was low. I had the intake manifold replaced when the engine was replaced. Could it have been bad or is there something that is causing it to go bad?

Tiny
Tamwa24
Mar 3, 2007.
The oil pressure should be checked with a mechanical gauge. If it is low then it is usually a main bearing or cam bearing (possibly oil pump).
The suction is the PCV system, and some engines will not run or run very badly with the oil cap off, because this interupts the vacumm flow.

I believe I would take the car to another mechanic for an evaluation of the oil pressure and cooling system. If the oil pressure is caused be excessive bearing clearence, I would have the engine replaced again. The remanufactured engine should be under warranty.

I have seen bad remanufactured engines. I replaced a 2.2-4 cylinder in a Cavalier with a reman. And it had no compression in one cylinder.

Is this a 3800?

Tiny
Mmprince3000
Mar 4, 2007.
Yes is it a 3800. Thank you for all of your help. This really sheds some light on all the problems we have been having the past two weeks.

Tiny
Tamwa24
Mar 4, 2007.