ive got a 99 ram with 318, i changed the radiator and have not heat now..i went back and put a new thermostat in still nothing. ive got hot hoses going to and from so i figure its gotta be blend door. im guessing its vacuum and i done something to it when replacing the radiator. Please help getting cold here.

 

Maybe your heater core is clogged up. Could try and backflush it. I think the blend door is motor actuated.

 

If the only thing that changed was the radiator, chances are, you just have a big air bubble in the heater core. Backflush it, as suggested, try and lose as little liquid as possible when putting the lines back on. (don't disconnect at the heater core, passenger side line has a splice in the middle, disconnect drivers side line at the steel tube going into the water pump.) Should have good heat then.

 

thanks guys, ill try backflushing it in the morning...is there a wrong way to do it, cause if it is im sure ill find it..

 

LOLOL. No. Not really. Just run water thru it both directions, backwards last. Then just hook it back up, and try and keep as much of the fluid in there as you can. Should work just fine.

Another option is to cut the passenger side hose at it's highest point. (which is, unfortunately, right by the heater core..... in a nice, easy to get to location.......) Install a Flush "T" there, with the cap facing up. Start the engine, crack open the cap, and bleed all the air out that way. Tighten it back down, and you should then have good heat. (once the engine warms up.....)

 

All so what would help is to put the front end up high, and the heat on hot/high while filling the rad.

 

back flush worked got great heat again and an easy 10min fix...thanks guys

 

Gotta love the easy ones.

Wrong time of year not to have good heat.....

 

Sorry to hijack, I am dealing with the same issue in a truck with a recent heater core replacement. Just want to be sure on the side to put flush T in. Is it the Passenger side for sure?
Mine is a 97 %.( was 5.2 originally if it matters.