Hi all trying to solve my heater woes in my 98 ram with the 5.9. Right now it'll blow heat for a few seconds then cool down depending on which vent it's coming from how fast and how much it cools down. if from the defroster it cools very fast the dash vents will stay lukewarm. I also have a mystery coolant leak somewhere on the engine I've been trying to find it but I can't see where it's coming from. The cooling is around the drivers side along the top of the oil pan and on the starter wire. it drops down onto the front difff from there and onto the ground. Anybody got any suggestions?

 

Air pocket in the heater core. Need to fix the coolant leak.

Might be coming from the timing cover, the bypass hose from the w/p, to the intake, or even from the freeze plug behind the motor mount......

 

thx I'll take a look.

 

Another spot to check for the coolant leak is the metal tube coming off the water pump to the heater line that runs along the left side of the engine. If that o-ring as been disturbed recently or is for some reason worn out it could leak there aswell

 

Get a pressure tester loaner from a parts store and pump it up to find the leak.