Heater problem, here, too

[JohnnyBravo]

This is not a problem with my car, but a fellow members car (who happens to be out of town on his honeymoon right now). I'd like to see if we can figure out how to fix his heater issue before he gets back.

It's a 1993 RT/10. The blower works fine (you can hear the different speeds, etc) but little, if any, hot air comes out through the vents. You can feel that the air that WANTS to come out is hot, but it just barely seeps out of the vents. There is almost no force behind it, regardless of fan speed.

The cable loop on the top of the heater valve is connected and works as it should. That was the first thing we checked. Thermostat is new, and nothing leaks.

If the blower works, and the air gets hot, but doesn't come through the vents, what is the problem? Is there some kind of vacuum activated door that controls air flow?

Where can we start looking?

Any input would be greatly appreciated. I'd really like to help a brother out.

JB

 

[Steve-Indy]

Aside from a duct problem...are you SURE that he has the controls set correctly??

There has been MUCH confusion on this over the years...as one can "cross control".

To get heat, the middle and far right knobs MUST be turned to the RIGHT of center (one can have heater core flow open with far right knob on "red", but NO HEAT because middle knob is on the LEFT side of center. (actually, I run the Vipers just this way in the summer...for a few miles... after I have changed coolant to be sure all air has been moved thru heater core and out...noting that the cockpit stays cool until I dial center control to RIGHT of center as a test).

Just a thought...let us know.

 

[carguy07]

Assuming you know that heat does not come out of the upper vents?

http://vca2.viperclub.org/forums/showflat.php?Cat=&Board=UBB14&Number=603647&Forum=UBB14&Words=heater&Match=Entire%20Phrase&Searchpage=0&Limit=25&Old=1month&Main=603633&Search=true#Post603647

 

[JohnnyBravo]

Gentlemen, thanks for your replies so far. I believe I had his heater settings correct when he first mentioned to me that it wasn't working well. I will double check them again.

I also understand that no actual heat comes out of the center vents, but his doesn't seem to come out of the bottom ones much, either. I didn't really check the defrost setting, but I suppose I can do that next time, too.

When I set my GTS heater position selector to floor, it will melt you out pretty quickly. Feet get toasty and the whole cabin heats up very nicely. Even though his is an RT/10, it doesn't seem to get very hot at all.

Are there some vents which control flow somewhere behind the dash? Are there any vacuum lines in the engine compartment which effect heat and which are visible with disassembling anything?