I have a 2000 Malibu and here is my situation. The low coolant light was coming on but temp and fluid were OK. While driving the other day just before I got to where I was going car started running rough. When I started the car again to leave it started smoking a lot. I had the car towed home and the coolant is in the oil. I read the sticky post about the manifold gasket but was wondering how do I know if it was the intake manifold gasket or one of the head gaskets. I already began taking taking some things apart and I am at the point to remove the lower intake manifold. Is there a way to check if the head gaskets are bad (compression test maybe). According to the temp. gauge the car was not over heating. Thanks in advance.

Most like a bad lower intake manifold gasket, and it will be obvious when you remove the manifold. The plastic framed gasket will be deformed, and you will likely see coolant mixed with oil pooled all around the upper engine, and maybe even under the valve covers, and you may see what looks like orange (Dexcool colored) rock sugar in some of the exposed coolant passages.

Doing a compression test would not hurt.

Thanks for the reply. I took off the lower intake today and there was a port that was bad deformed. I bought the felpro kit and was wondering if you put any rtv on the gaskets or anywhere else besides the two ends. Thanks

As I recall, only on the ends. Followed directions posted several places, including the FSB. I used the Dorman kit. Also new seals/0-rings on the injectors and fuel rail inlet/outlet.

Sorry to butt in but I have a similar problem. So far no overheating but I've got oil in my coolant reserve tank. I have no idea if there is any coolant in the oil (my wife just took it in for an oil change and reported nothing). I figured it's either the head gasket or the intake manifold. Anyone have any idea? How can I better diagnose the problem?