UIM or LIm gasket failure
99 buick park avenue L36
and it is drinking coolant
I think a call to ed is in the future

Is it knocking? Has the oil been changed?
Ed Morad is a awesome guy to deal with

Ed

Series II L36 drinking coolant, no visible leaks is generally a good indication that the upper intake manifold has failed or there is a gasket that has failed.
In any situation, a new redesigned UIM and full gasket set including lower intake manifold gaskets generally is the way to go, however, you may want to further diagnose the problem on that car
Moved to 92-99 for the gurus to play with for a bit

well it is my brothers car and he said that it is drinking coolant and the oil is about 300 from needing changed

I would highly suggest to him that he quit driving it now and drain the oil ASAP. Otherwise, it might cost him an engine.

I suspect the UIM AND LIM gaskets need to be replaced. I wouldn't do one without the other, that'* for sure.

Stop driving immediately.
Drain the oil.
Get an APN UIM.
Get the aluminum LIM gaskets.
Get rid of the DexCool forever.

Doing the work yourself will run about 200 bucks for parts.

I assume the level on the dipstick is the level when not running?

If so, that'* a gasket issue. An UIM would fill the cylinders and cause a hydrolock. Either way, I'd question the motor depending on how long he'* driven it that way.

well a little update for you all. it is going to the shop and we will see what happens. the oil was not drained till it went to the shop and knowing my dad it will be replaced with a oem upper and lower. I will let you all know later when I know more. I figured I was right and you all helped confirm that.

What year and model is this car? Something other than a 92-99?

99 buick park avenue non ultra