Another Heater

[Bernard Thompson]

Heater problem;
1990 RRC I had the system flushed this fall. The heater coil was done separate and had good flow. When the revs are up (12-1500) get good flow of hot air. At idle, it is hot then starts to blow cold. It will continue cold until 1) turn fan off, let heat gather, turn fan on again, one or two minutes cycle time. 2) Light turns green revs increase, still takes a minute.
This is all on defrost, no air flow to driver’s feet, little to passenger.
I have not replaced the fan resister, high or off only.
Are the control doors not closing proper? I would prefer to take it apart only once.

Thanks
Bernie
Northern MI

[BullDogSix]

Sorry, I don't have an exact answer to your problems. It sounds like a combination of problems perhaps. Have you checked your thermostat? It might be stuck open with all of this super cold weather we are having here.

Where in N. Michigan are you?...I'm in Traverse City. I've just bought a 1994 RRC LWB...but I have not picked it up yet.

[Bernard Thompson]

The car runs good on those mines days and the warmer ones.
It should be an easy job and take one option away.
thanks
bernie

[OkieRover]

The heater box has many flaps. I would guess that one or more of them are not working.
The cold air coming in is coming in through the fresh air intake just above your hood, looks like an air scoop. You could block that and see if the cold air quits. That would confirm that one of your flaps is not doing what it is supposed to do.
There are mechanical, controled with a wire, and a single vacuum flap. Maybe if you are lucky the vacuum line failed and fixing it will get the air through the right vents.

[Bernard Thompson]

Thanks Okie,
That’s a grate ideal of covering the air scope.
From what I have read the end of the wire on the flap does come lose.
Good web site, it helps.
Thanks,
bernie