1991 2500 No heat, at a loss here
 

Hello all, Im a new member to the forum. I also have a no heat issue. Here is what I have checked. System has ac. Replaced the ticking recirc actuator which obviously did not fix problem. Removed temp actuator...opened cover all gears looks fine, hooked up power and worked cold/heat control....motor turns. Have replaced thermostat. No worky. All other controls work fine goes from defrost to floor and blend fine. Inlet hose from manifold to heater core is warm, output hose to upper connector of radiator is warm, also with radiator cap off I can stick my finger in radiator and feel warm/hot water returning.....seems like heater core is fine. Any other suggestions would be greatly appreciated.

Re: 1991 2500 No heat, at a loss here
 

Welcome to the board!

The heater hoses should be HOT not warm.

What temperature is the engine temp gauge showing?

What temperature thermostat did you put in it?

So many thermostats are bad right out of the box lately that I will only use STANT brand. STANT is a supplier used for thermostats when the vehicle are assembled.

Re: 1991 2500 No heat, at a loss here
 

I put in a 180 from thermostat from Oriellys, they did not have a 195, system blows cold air.......Thinking that may even though my temp actuator is working that maybe the door is unhooked from a cable maybe if there is one. Even with a 180 I should still get some heat albeit not as hot as a 195. Tmrrw
I will unhook heater hose and back flush with hose and see what happens.

Re: 1991 2500 No heat, at a loss here
 

There are no cables for the temp door. I have heard of the door breaking lose, and not moving, but it is very rare.

180 is to cold for the ECM programming and will cause problems if left that way.

If you have changed the water pump recently, it may have the wrong pump. The serpentine belt turns the pump the opposite direction as the V belt setup.

Checking for a restricted heater core is not a bad idea.

If the air flow out the vents feels weak you should check to see if there are leaves and debris that need to be cleaned out.
Instruction and photos at this link:
http://www.chevytalk.org/fusionbb/sh...php?tid/282054