1999 Pontiac Montana Repair Question
Pontiac Montana Gas Problem
That's what you pay mechanics to figure out. There could be a leaking cylinder head gasket. It could be as simple as a sticking thermostat. To identify a leaking head gasket your mechanic will draw air from the coolant reservoir through a glass cylinder with two chambers partially-filled with a special dark blue liquid. If combustion gases are present, the liquid will turn bright yellow.
17,280 answers provided