Heater Core backflush

[Steve Roseman]

Has anyone backflushed their heater core with any success? I still get heat but not like I should. I was wondering if it would be worth my time to try to backflush or just get a new heater core.

My engine temps are fine, so that's not the problem.



Thanks, Steve

 

[Don M]

Sounds like the heater control valve to me.



Don~

 

[Steve Roseman]

Thanks Don, I'll check it out. Have there been any common problems with the heater control valves?

 

[MoparDave]

Maybe the blend door in the heater platinum is not functioning properly, or it may be as simple as a T-stat stuck open.

 

[Steve Roseman]

The thermostat's working properly, operates at about 170 to 180. The air mix door works I think, I can recirculate the air and it's much warmer. When I use the floor heat it draws some outside air.

I still have enough heat to stay warm, it just doesn't put out the heat like I figure it should.

I can feel the difference on the lines going to and coming from the heater, the return line is noticeably cooler. I just figured the flow is reduced enough that it has a chance to cool too much.

I had a Caravan that I replaced the core in, it was a cheesy core. The design principle was good, but way too easy to plug. I don't know if the Rams used the same design.

 

[illflem]

Did you park under any trees dropping leaves this fall? Small ones can make it though the grill in front of the windshield and plug the airflow though the core. I run into this problem all the time in the early winter. Our trucks don't have heater control valves that can become stuck, the hot coolant flows freely though the core at all times. The valve was eliminated on most vehicles years ago to keep the core from getting full of sediments when the flow was stopped or the valve sticking. What we have now is a blend door that opens according to the position of the red/blue knob, this adjusts the ratio of hot to cold air. It is possible for this door to get stuck open to cold air even with debris like a mouse nest, or the vacuum line to it to come off or get kinked. Sometimes you can hear if the door is running, unfortunately the truck needs to be running at the same time, makes it harder to hear. I don't think you need to flush anything and your fix won't require any parts, just a lot of tearing into the underdash to track it down.

 

[Doc Tinker]

Steve, you didn't indicate the age of your truck. Newer trucks shouldn't be experiencing the plugged heater problem. If you do flush that heater, I recommend letting the Radiator Shop in your area do it. They have equipment that will flush out the core without blowing it apart.



If you flush your cooling system and fill with fresh coolant every couple of years, you probably will not have to flush the heater core.



Doc