Are the heater hoses hot after driving? If the inlet to the heater core is hot and the out let is cold, could be a plugged heatercore.

How is the coolant level? Low coolant level can be enough to keep the car fom overheating, but not enough to make it through the heating circuit.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D