2000 JGCL 6cyl -

Heater blows cold air (it is cold outside) and won't heat up.

I had a leak in the radiator so I just replaced with a new thermostat and new radiator. I checked the blend door actuator through glove box and can see the motor turn when I switch dash control from AC to Heat. The re-circ door also works properly. Hoses in and out of fire wall (from engine to heater core) are heating up to same temp and pressure.

I have been reading about these options but I'm not sure if they are the same thing just using the different names. Any suggestions and direction on what order to attempt and exactly where the valves and control panel may be would help a lot.

1. Back flush the HEATER CORE

2. Faulty TEMP CONTROL PANEL

3. Faulty or Disconnected DIVERTER VALVE

4. Check WATER CONTROL VALVE (is this same as diverter? is it the blend door?)

5. Replace HEATER CORE (big $$$ so i'd like to trouble shoot all other options first)

THANKS!!!

 

try flushing the heater core. thats what i had to do to mine

 

First thing to do as stated above is flush the heater core. It's relatively quick and easy, simply disconnect heater core hoses from engine, and put garden hose to one hose, and let the other hose empty into a bucket or something. Perhaps use a sprayer fitting for the garden hose and put it as close to the heater core tubing as possible. If that doesn't work, try removing the blend door motor and flipping the door by hand to see if you get heat in one position or the other. Let us know what u find out!

 

The reverse flush did the trick! Glad I did some trouble shooting before jumping into replacing the heater core like many people were suggesting...saved tons of money and time.

While flushing I also noticed the feed and return hoses had some blockage so after flushing the hoses and core I now have better heat then when I purchased this beast 6 years ago.

Now I gotta find a Throttle Valve cable and replace the brakes and I'm back on the road.

later

 

Badass; yeah that drives me nuts people saying a heater core needs to replaced when all it needs is a good flush. Good luck with your project!