My 99 durango is blowing out luke warm air when i put on the heat. People are telling me all i need to do is flush out the heating core. Has anyone else had this problem before and is flushing out the heating core going to fix it.

 

Flushing out the heater core works sometimes (quite easy to do aswell), but other times it wont, or if it did it would last for a little while. What happens is grime builds up on the veins(its just like your radiator but smaller) and somewhat insulates the veins preventing the heat transfer to the fins which radiate the heat into your cabin.
What people occasionally try is removing the feed line at the engine which is aside the thermostat housing, and the return line that comes from the coolant pump and flush with a garden house in both directions. I dont recomend removing the lines at the fire wall because the lines can be adheased pretty good and you take the chance of busting the heater core if not carefull.

 

Mine lasted two months after a flush before it started to get low on heat again... Looks like it's time for a new core for me...

 

Or just flush it every 2 months. I would much prefer that to replacing the thing...

I can attest to how hard it is to get the lines off of the heater cores lines. I acctually ended up cutting mine at the core. They were 8 years old anyway. If you are concerned with damaging the core you can pull the lines from their other ends. One is at the t-stat housing (it's a tight squeeze to get to) and the other is at the water pump.

 

I am not afraid to tackle anything... A heater core would be fine with me! I just don't want to pay for the parts!

 

That makes two of us not afraid to tackle the issue but it sucks and I'll tell you why. You bust your *** for 9 hours feeling like you aren't getting crap accomplished and when it's all said and done your ride doesn't even go faster...

 

I would just flush it. My dad clogged the heater core on mine with stop leak for the heater core leaking. The heat was not even warm. Just before I replaced the core, I flushed it with the garden hose and tried the heat. It worked perfectly apart for the coolant smell.

So if yours isn't leaking, just flush it.

 

I have had this problem for years. I flushed out the core going both directions about 2 years ago. I did not notice a difference. I had used some kind of radiator leak stopper about 4 years ago. I believe this is part of the problem. Does replacing the core really take 9 hours? The vents hardly put out any heat at all. I have noticed that the heat controls(the plastic) are very warm. Could there be a duct that came loose?

 

The controls are warm due to the electricity running through them, any resistance in the switch causes heat. A good example of this is the interior dimmer switch. The more you dim the interior lights the more that dimmer wheel warms up as it is just a variable resistor. As far as the heater core taking 9 hours. Yes it will take that long unless you go ***** to the wall start to finish. For me part of those 9 hours was just trying to get my head into the game so to speak because it's one of the most "not fun" jobs to do on pretty much any ride...

 

+1 on a slow easy flush in reverse direction from the fire wall.

Replacing coolant within every 2 years will keep the anti-corrosive property in check. Otherwise, rust away and clogging occurs.

+1 on replacing the heater core SUCKS.

IndyDurango