another heater problem

[Grunizzle]

I have a 91 with the 4.0 v6 with no air conditioning. My blower works great and I have solid air flow at all settings but I just do not get hot air. My engine temp gauge is reading where it should be. The air just barely changes temperature from full cold to full heat. I do not know where to start troubleshooting at.

 

[rtg143]

When the engine is hot, feel the heater hoses and see if they are hot.

 

[ElleShooTiger]

When the engine is hot, feel the heater hoses and see if they are hot.

There should also be a heater valve on the lines going to the heater core, check for heat on both sides of the valve.

 

[Grunizzle]

I went to check the heater line tonight and one of them is really hot all the way into the firewall, the other one is cold.

 

[Grunizzle]

no one has any ideas?

could the heater core be clogged?
Where is the heater control valve located?

 

[HareRazor]

I would disconnect the heater hoses and hook it up to your garden hose and see if you get much flow through it.

 

[Grunizzle]

Well tonight I was driving it around and wiggled the heat slider back and forth a few times and then my heater seemed to warm up. It was pretty warm, but not hot. I checked the warmth of the heater hoses and the one that was cold yesterday is warm now. I really don't know whats up

 

[COPPERHEAD85]

You may have to back flush the heater core.
Disconnect both lines to the core,you will have to cut up a garden hose so you can clamp it on the side that is cool, and run some water thrugh it.Just don't get to happy with the water pressure from your outside hydrant from your house.
It would be a good idea to cut a piece and put on the side that was hot so it will dump on the ground not under the hood.
Again be very careful not to crank up the water coming in,take your time.I have done this before with great results.