I bought this vehicle used. Haven't had it a year, and it is costing me a fortune. While I had my truck at the dealers to have some warranty work completed (transmission, lower intake manifold gasket replaced) they managed to clog the heater core. I'm fighting the dealer right now to have them pay for it. Prior to having the transmission and gasket replaced I had heat, now I don't. Instead of replacing the heater core we're going to have a pressurized backflush of the heater core completed and a regular cooling system flush completed. I'm more pissed off at the dealer than the vehicle at this point!!

My heater stopped working. Diagnostics show a very warm inlet hose to the heater core and a cold outlet hose. Is very evident that the heater core is completely clogged up. Another trademark of General Motors. This is not new either. As an ex-tech I saw this repeatedly in the 20 years plus I worked on cars. Why can't GM hire a different manufacturer who would make better heater cores that will not clog as theirs do. MAYBE I SHOULD START BUYING JAP CARS. My wife owns a 96 Nissan Maxima with 155000 miles. I don't remember the time we had a problem with this car. Besides filling the gas tank & replacing the oil we have never had a problem with this super-reliable car. Oh yes I almost forgot the OEM heater core cost $120. That's dealer price compared to $59 elsewhere.