I think I have a problem with the heater on my '93. While sitting at idle ( at operating temp 190 ), I get at best luke warm air from the heater with the control set at any temp. The faster the car goes and the higher the RPMs, the more heat I get. The fan motor runs and does vary speed from 0 to 10.
Is that normal for a C4 heater?
I took the car to a dealer and the mechanic told me he did in fact have the same thing happen when he tested the car but did not seem to think it was unusual. I would tend to think that as long as there is coolant flowing through the heater core, you would get a constant temp out of the heater regardless of RPMs of the engine.
If any of you would care to try this and let me know if you get the same results, I would greatly appreciate it.

Glenns

My 93 Ruby has the auto climate control and I do not have that problem. It blows hot whether at idle or at speed. The fan blows at the speed dictated by the desired temp in the car. I don't think it is normal for yours not to blow hot at idle.

Glenns...are you getting air flow thru all the vents??? I know that sounds like a strange question...but Hubby had some trouble with his C4..turned out to be a plastic T-valve...after months of trying to trace the problem...turned out to be this valve...a $5.00 fix and 20 minutes of time.

Thanks Grego. That is the answer I was looking for.

Yes Debbie, all vents work fine. The mechanic also says he can hear/feel the door flap open for heat.

I talked to the head mechanic of a GM dealer shop last night. He has never heard of the problem before. Told me to bring the car in Friday and they will dicsonect the heater hoses fromthe engine and do some kind of pressure test to see if coolant is flowing through the heater core the way it should.
I also found out my warranty will cover my rear wheel bearings so that is at least one good piece of news. Now I have to make sure it covers the power booster also .

Thanks for the responses !