My wife and I just purchased a Ponitiac G5 GT as a daily driver that was a demo with 5000 miles, so we are the official first private owners. When we got it home we noticed the antifreeze was low and so just filled it up assuming it was low from the factory. Well, it wasn't. A couple months later
it was low and so we took it to a Ponitac dealership with the expecation that they would fix it.

They couldn't find the leak, so they pressure tested the coolant system. Still nothing, so they dyed the coolant and told us to go drive it. Did that, took it back, and they said it was the head gasket and they said they replaced it. We have the paperwork that says they did that when we picked it up thinking they had fixed the problem.

Last Friday the coolant was low. So back to the dealership it goes. Now they are saying they didn't replace anything on the car last time (even though we have the paperwork saying otherwise) and that they still don't know where it is leaking. Unfortunately, we think that the antifreeze is getting into the oil because what appears to be frothy snot formed on the oil cap. Dealership is saying that is just condensate, but that sounds like a load of BS to me.

They now want us to just drive the car because they don't know what is wrong with it. This obviously doesn't sound like a solution to me.

Car is GM certified 4yrs, 48000 miles. Has 13000 miles now. 100000 mile powertrain.

Lemon Law is first year/12000 miles, 3 visits unresolved (we are at 2).

Options? Opinions?