hi.Just bought my first Dodge a yellow sport xtra cab 4wd with a 5.9.I like it and the mileage is better than I expected,but my heat goes away when I am off the throttle.Engine temps are normal but i will try a thermostat anyway and maybe bleeding any traped air.Is there anything else I should look for?Any tricks from you seasoned mopar guys?

 

When I have encountered this situation with any vehicle in the past it was due to being low on anti-freeze. During driving the rpm's push enough fluid around so it does get into the heater core hoses, but at idle the low level prevents fluid from traveling in sufficient amounts through the heater coil to provide cab heat.

If you are going to replace the thermostat, try this trick to prevent the build up of air pockets. Take 2 regular aspirin and while manually pushing the thermostat open, insert them to keep the thermostat open. Then install your thermostat and fill the radiator. The aspirin will keep your thermostat open long enough to allow antifreeze to fill into the areas where air pockets can normally develop. Within minutes of starting the vehicle, the aspirin will dissolve and your thermostat will operate normally.

Good luck and welcome to Dodge Forum.