Expert: Roland Finston - 1/7/2012

Question
2001 Sebring, LXI Coupe, 3.0L V6 - Cabin heat problem.  Air blows cold unless engine rpms are above 2. Prior thermostat replacement - 1st time temporarily fixed problem, 2nd time (1 year later) mechanic said thermostat was good, but I had him replace it anyway - did not fix the problem. Not losing coolant, not overheating (temp guage stable at mid range).

I've read through all your prior relative posts and think I understand diagnostic steps i.e. check for equal temp of hoses, check no blockage in radiator, no blockage in HVAC and possibly actuator door. I'm suspecting (from your prior posts, and mechanic added coolant directly to radiator?) air in system.  

Am I on the right track?

Also, have printed off instructions for draining and refilling 2.7L, but can't find any for 3.0L. Are they the same?

Janell

Answer
Hi Janell,
The instructions for changing/refilling the system points to the need for a part that is used at the top radiator cap opening, MB991871, which appears to have a fitting which allow the insertion of fresh coolant and for the release of trapped air apparently in a sealed manner which may move the air out more effectively than without the part, but nothing specific is offered as to the procedure other than to see the "manuafacturer's instruction for the special part. If the two hoses at the firewall are not very similar in temperature then 'air trapped' could be the issue or of course the heater core may need to be back-flushed to improve the flow through.
Lastly is the issue of the blend air door (or temperture door) of the control unit. It appears to be a mechanical connection between the temp lever and that door lever. You might do well to verify that there is a positive connection and that you can discern movement of that air mixing door which controls the temp of the air to the cabin. There is no further mention of any wrinkles to be aware of with the 3.0L engine. So check with a Chrysler or Mitsubishi dealer about that refilling part for the cooling system, maybe read the instructions before buying it to see what it is supposed do, etc.
Roland