2004 Durango Heater Problem

I have read the other threads and I am not sure that my problem is the same as theirs.

I recently had the water pump replace (late last summer). Now that it is winter, my heater does not blow hot air (warm air at best).

One thing I have noticed is that my temp guage only goes up about 1/4 of the way - even after extended driving.

Do you think the problem is the thermostat, or should I look to the heater core?

I'd probably clean out the heater core. I've done it to my 99, it only takes a few minutes to do. If your temp guage is in the normal zone that just means your thermostat is indeed working. Good Luck!!! Just follow tommychau's instructions you'll do fine.

Indeed working yeah, it's probably stuck open.

Also a good possibility, on the 5.2,5.9 I believe the stat is located underneath the alternator. To get at it you'll have to pull the alternator off.