Trying to figure out why heater does not get hot enough; replaced old thermostat with new factory 192 degree the other day and engine warms up a lot quicker but heater still does not get hot, gets warm; could heater core be a problem, I don't think this model has a heater control valve, at least I can't find one under the hood. It is 98 Durango SLT plus 5.9L 4x4 with 172,000 miles on clock; runs great and still a beautiful car. Thanks for any advice.

 

Heater core may be plugged, mine did that. Take the hoses off and flush the core reverse the normal flow and see all the junk that comes out.

 

Ok noman I will try that for sure, that makes perfect sense to me. Thanks

 

Before you start throwing parts and money at it, check your hoses. Are they both hot at operating temperature? Is one hot and one cool? If both are hot, you may have a blend door issue. If the return hose is cool, then your core may be plugged. On that you can try to reverse flush it.

 

Right. Another thing is, someone could have replaced the thermostat using one with a lower temp rating. Where is the temp gauge after full warm up?

Heater core flush here: https://dodgeforum.com/forum/2nd-gen...re-flush.html#

 

How many miles on the engine? Does the temp gauge move very far or does it stay low on the gauge?

 

mine has a different problem.... just my feet get cold, any other choice of which vents to blow out the air will get it so hot in there I have to turn down or crack a window open.... its a linkage problem on the plenum.... on 2 of my vehicles. is this possibly what you mean? Mine blows out HOT at defrosters or in my face just not on my feet...… it hadn't been terribly cold lately and I have 2 side jobs here to tend to.... those will give me extra cash to put towards the last few quirks I have to fix on my Durango.....

just thought Id throw that possibility out there that it could be a mode door or blend door issue within the heater core plenum...…

 

Back flushed the heater core today and hooked it all back up, gets a lot hotter now, looks like it working like it supposed to, all my vents and blend doors are working fine, goes to floor, dash, defrost and combination of both with no problem. Amazing this 5.9L runs just about as strong as my 08 Hemi Ram. Only had the car for about 3 months and really love it.