I have the same problem. I had no heat. So far I have changed the thermostat, water pump, Thermostat housing, all the hoses, the belt. I used the prestone flush kit. I poured CLR into the core and let that sit and flushed it. I used the radiator fill kit to eliminate any air. I even parked it on a steep incline to make sure I could get any trapped air out. After all of this, I still have very little heat. I can get 150 degrees out of the vents on a 50 degree day on the low fan setting. Any higher and the temp drops. I have pretty much run out of options short of tearing the dash apart and replacing the core which I doubt will do anything since it flushed just fine. It is not too bad now. I just don't know how it will be if we ever have a 5 degree day.

 

could be the radiator cap. seen that happen before too.

 

Hate to say it, but the core is what you need. I flushed my core day after Christmas and it got a lot better, but only when I leave it on the 3rd setting for the blower motor. My core looked like it was flowing fine too when I flushed it. But I know that it's the prob. On a side note, I also had the radiator cap pressure tested a week before I flushed it , it was no good and would not hold any pressure. The cap raises and lowers the boiling point, 3 degrees for every pound.

 

I think the heater core is one of the problems but the deffinately there is some kind temperature blending door issue because the fan blows very well.

 

does the A/C get cold? if the blend door will swing full cold, it should swing full hot. That's barring some physical blockage of the door, which probably isn't very likely.

 

i have the same issue in my 95...mine works well on 50 degree days but on cold mornings,it will do nothing,but blow ice cold air.how hard is it to get the dash out to replace the core?

 

tore into my 2002 ram 1500 today because I had no floor or defrost but vents all worked fine. Lots of noise on high. There were a zillion leaves in the fan area when removed. I found 3 motors and one (right behind the controls)controls the defrost/ vents and the white **** that the motor fits into had a broken off tang which limits the amount of travel for the door. It seems to be loose inside the plenum area so I smell a complete dash removal coming to get the plenum out for repair. Anyway, while I was playing with the different motors to see which one changed the defrost I noticed that the center motor( I think) activated a door which seemed to change the air from hot to cold. I took the motor off to manually close the door and I noticed the cold/ hot change. You may want to check this out. Has anyone tried to repair the white **** so the defrost door will open? It looks impossible to do without removing everything. ????

 

My dad just had his S10 have this problem, no heat.. He thought his Heater core went out, I told him it was the door not closing... He ended up taking it in, and sure enough the motor for the blend door went bad, $300 later it'sfixed, I wish he would have let me do it, I would have just locked it on heat until spring, and we could get a motor for it at the junkyard or whatever and saved a crap load of money... sigh...

JimK

 

I just wanna get blown.





i hope I don't lose my heat. My truck used to heat up fast and pump out some nice hot air. i hope the mods and new tstat don't change that

 

Oh man, I just can't wait to go out and tackle that blend door motor. Thanks for all of your inputs guys. I really appreciate it.