I have the same issue with my 95 1500. I did as you are supposed to. Check the coolant level on an incline, It still has the air in the Heater care but no leaks anywhere. Is there a special flushing technique for the heater cores that I may have missed?

 

ok this is the best way to do it...

ok lets say you have no coolant and are now beginning to add..

1. put the truck on incline so the fron of truck is highest point/ above heater core.
2. fill radiator.
3. turn heat on full blast/defrost
4. Start the truck
5. Add coolant accordingly when the thermostat opens.

 

Turning the head on full blast does nothing. The Ram does not come stock with any kind of valve that opens/closes the coolant flow to the heater core.

 

whenever these dodge truck spring a leak under the hood somewhere, it sucks in air at the same time. sence the heater core it the highest point of the cooling system, well air rises and goes right to the heater core. it the leak is coming from tward the front of the engine, its in the water pump area. it could be a faulty water pump. if it was recently replaced then thats more than likely the spot. take it back to the shop that replaced it, im sure they offer some sort of warrantee to thier job. they will pressure test the system and find the leak. if they cant find it. tell them to let it cool down over night and test it in the morning also. eventually your problem will get worse so dont go to far from home with it

 

I discovered this also when burping mine...

 

Anybody ever check the water pump heater core bypass tube.

 

Nine year old thread????