There's a PI out for a coolant problem. It's complicated, but the general notion is vapors coming out of the overflow tank. If you once had a leaky heater core and had it replaced, and any coolant got left in the carpet, it will continue to smell even after the problem is fixed.Has anyone with the "geiger-counter rattle" in the right side of the dash had it fixed successfully? My car is going back in for a fourth attempt at a repair. Oh, and the coolant smell, and brake problems...
I had a rattle that I thought was in the dash. Turned out to be the speaker trim ring on the passenger side. You sure that's not what's causing it?
Good luck getting the problems resolved. Do you have a case open with GM's customer support?