Explain this one to me (heater core vs AC)

[occupant]

So for the last year plus, the heater core has leaked in our Durango. Shut it off and restart and it'll make a sweet smell, right? Temp gauge would see halfway from 210 to 260 if you let it sit long enough in traffic. Let it idle and the AC gets hotter up front.

So I finally had enough of this not being able to go into drive-thrus or sit in traffic bit and decided to bypass the heater core with a 78 cent pair of clamps and a coupler that was already in the system holding two heater hoses together. Works. Engine doesn't overheat when you let it sit and idle. Doesn't overheat in traffic. AC works better but it still gets hot when you sit at idle. Engine stays under the 210 mark but the AC gets hot, and only in front. The rear AC stays ice cold. So it's not a freon leak. I'm stumped unless there's some kind of expansion valve in the front evaporator only or something.

Vehicle is a 2000 model Durango with 2WD, 318 engine, front/rear AC. What could cause the rear AC to stay cool all the time and the front AC to only be cool when we're moving at city or highway speed? And if it requires pulling the entire dash, forget it, I'll scrap it before I spend $700 in labor to deal with that. Ridiculous that it requires that many labor hours to replace a heater core let alone anything else, should be accessible from under the dash or in the engine compartment.

 

[Jimmy9190]

I read on the Dodge Forum this can be from the condenser being clogged with dirt and debris, they say rinse it off with a water hose but no high pressure so you don't mess up the condenser fins. I also read it could be the fan clutch is going bad and causing the warm AC, and if the radiator is clogged it will cause warm AC too.

This makes more sense to me: The blend doors in your 2000 are vacuum actuated. Have the AC on and look under the HVAC housing in the passenger's footwell. There will be one cold line and one warm line. The warm line feeds the front AC, the cold line feeds the rear AC. Next to it is a vacuum housing with either a black or clear vacuum line. Check that vacuum connection and see that the line is not broken or disconnected and/or check for a broken plastic switch on the vacuum housing.

I do not know much about AC, I read this stuff on www.dodgeforum.com. They have a section for Durango owners. If you have not been on that site it might have some useful info for you.

Good luck with it.

 

[demarpaint]

The condensor could be clogged with dirt as Jimmy mentioned, and not cooling the system down fast enough. Try running cold water from the garden hose over the condensor while the A/C is running and the engine is good and hot. Do this while the problem is rearing its ugly head. See if the cold water running over the condensor eliminates the problem. The try cleaning the condensor and see if that helps any. Post back and let us know what happens. HTH

 

[meep]

there is something else going on for the engine to hit 260 at idle. haven't seen that in a belt-driven fan (assuming it is?) this side of 1990.

Check fan clutch. if electric fans, make sure they are spinning the whole time the compressor in engaged. at those temps if you rev it, it should sound like a big roar (completely engaged).

agree to check/clean cooling fins in BOTH front rads

do you have a cabin filter? may have dirt buildup on radiator in dash. pull the fan out and see if you can hit it with HVAC cleaner spray from home depot. rinse with a hose, carefully.