Drove my 2800CS in cold temps for first time. At idle standing still there's sufficient heat coming from the vents. However, at 60+ MPH the vent air becomes lukewarm. Fresh air flap works correctly by switching fresh air completely on / off. Lower "mixture" flap by footwell vents can be seen opening and closing. I cannot observe the upper mixture flap without first removing the blower motor (not too difficult). Coolant hoses in /out of heater core become hot, but not quite as hot as other radiator hoses.
Can this symptom result from any other system air leak, besides an upper mixture flap not closing completely? As an experiment I placed towels on either side of the fresh air intakes to the blower assembly. This allowed air vent output to become acceptably warm (but not super hot) at 60+MPH.
Thanks! -H
Can this symptom result from any other system air leak, besides an upper mixture flap not closing completely? As an experiment I placed towels on either side of the fresh air intakes to the blower assembly. This allowed air vent output to become acceptably warm (but not super hot) at 60+MPH.
Thanks! -H