If the engine isn't overheating, I would say no. If the heater core hoses are both hot, then coolant is flowing through it. Now, you will need to check the vent doors in the HVAC duct work under the dash. I'm starting to wonder if one of the vents isn't opening enough to allow heat to enter the cab. Do all of the settings work? For example defroster, heater, ac vents. Have you or anyone else checked that area?
Tuesday, December 9th, 2008 AT 10:32 PM