Re: 1991 Ford T-Bird Heating Problem?
1) Coolant level is low, preventing good coolant circulation through the heater core. If this is the case, have the system pressure tested, as this is indicative of an internal coolant leak through a damaged head gasket. This is quite common among the 3.8L V6 T-bird.
2) If the coolant level is fine, there may be blockage in the heater core. Have the system reversed flushed to clear any sediment. If that doesn't fix the problem, you'll have to replace the heater core.
3) The ductwork in the car is controlled by vacuum lines that connect to the heating/ac controls in the dashboard. A leak could result in the fan pulling outside air into the car. If this is the case, you should be able to hear the whistling from the vacuum lines. Check under the passenger side of the dashboard, where several of the vacuum lines run. One of them may have been kicked loose by a restless leg.
Last edited by janeuner; 01-16-09 at 08:49 PM.
Reason: Third possibility