My A/C is leaking in the cab and has ruined the carpet. It appears that the insulation in the evaporator housing (cold coil) has come loose because I can see condensate on the outside of the plastic housing and I was able to unplug the drain from under the hood which helped some.

My question(s): should I buy a new insulated housing and install it? Is it possible to just remove the old insulation and replace it with new insulation?
If anyone has had this problem is it a huge job?

I'm just retired at 68 years and haven't done much work on vehicles since I overhauled my 1973 Datsun pickup back in 1979. Older and stiffer and can't get under the dash as easily as I once did although I am not completely out of service yet.

Comments and advice appreciated.

 

Good lord man! why in the world did you wait so long to retire? I admire your longevity and stick to it ness! I bailed at a much earlier age from my vocation - now just working in a semi-retired mode. I can't answer your question unfortunately - just wanted to say hi! and congrats on retirement!

Cheers

Mike

 

Well, it's a long story. All I ever wanted to be was retired, honestly. But one thing and another kept putting it off, mostly money. Now that I am retired it's time to fix up my 1994 diesel. Mechanically it's great I need to redo the interior etc. maybe a new paint job. I have one picture that is pending approval and will post a better one when the sun shines again. Thanks fore the hello have a great day.

 

I'm confused, if your seeing frost on the heater box, more than likely its becase the AC is stuck on, typically its because the hi-low switch is stuck on or you have the AC system overcharged with freon, there is no insulation inside the box or on the outside of it, unplugging the hi-low will stop the ac or turning the ac/vent selector to any other posn than defrost or AC

or I missed your post completely and your saying the heater core has sprung a leak and is leaking antifreeze into the cab.

congrats on retirement!

 

No - not frost just condensate and water running down on the floor. from both the condensate from the outside of the heater core cover and probably the drain leaking also.
As humid as it get here when the AC runs there is a lot of condensate that should run out the drain that discharges under the hood (on firewall) and runs on the ground. Instead it is ending up on the carpet.
I had the AC coil replaced about 3 years ago and I suspect the problem originated from that job.

 

pull the carpet back to make sure the seal is good where it exits thru the firewall, you could RTV it if you have to (instead of pulling assy) IIRC the lower half of airbox has screws to hold it together, check the seams to ensure they are tight.

 

Well thats a thought. I havent checked where it exits the firewall from inside the cab. Partly because of location. I will do this later today. Thanks for the suggestion

 

Nickg - I looked and really couldn't see much. Probably best to go ahead and pull the heater core case and inspect everything from the inside so I can see just how the thing is put together. I need to wait until I finish a painting project that I'm working on before tackling that. Just never torn into the thing before and was fishing for advice from someone who had.

 

not really an easy job, you will have to evacuate the AC and have it recharged later, anytime you open an ac system you need to cap off the system, if its left open to atmosphere it will asorb moisture and you will have nothing but issues with your ac.

should be easy to see the drain, with carpet pulled back.

I'd suspect your hi-low switch is stuck on, easy to see if you leave vent in ac or defrost, and go watch your compressor it should cycle on and off every 8-10seconds, if it stays on longer or does not cycle, suspect your switch.

you can also recheck to make sure the drain is clear, if its plugged up the 'water" cant drain and that will cause what your seeing as well

 

Nickg,
Well I ran both the AC and defrost and the compressor cycles on every 12 seconds and off every 10 seconds (I wasn’t aware of that). I also tried to see if it would leak after a few minutes but it’s too cold and humidity is too low to create much condensate. I removed the carpet and the rubber pad around the drain but couldn’t see behind the drain flange. I could feel something soft between the drain flange and the firewall. I am beginning to suspect a rubber grommet/seal that has dried out between 1994 and present that might be causing the leak. I should buy the Dodge Service and Repair Manual to see what I need to do to confirm and replace this. (Been looking for an excuse to buy the manual anyway) I have attached a picture that might help explain.

 

mine used to drip there. The drain comes out on the other side of the firewall. To stop it I found a 2 or 3 inch long piece of rubber hose that fit snugly on the drain tube and just shoved it on there. Hasn't dripped into the cab since.

 

That almost seems too easy doesn't it. I haven't gotten back to this problem yet as I am finishing up a small remodel of the house and other honey do things. The thing hasn't leaked so far this year which is really weird to me. I will give it a try that's for sure and I thank you for the tip.

 

The earlier Dodges had a rubber piece that fit over the plastic drain on the outside of the firewall, the end was squeezed together to keep mice and such out, but the part that was squeezed together used to stick together and stop the condensation from draining out. This filled up the heater plenum until it found a place to drain out inside the cab. The water would also transfer the coldness from the evaporator core to the plenum wall and you would see condensation on the outside of the plenum inside the cab. Just like you have, you can actually see how high the water level is inside the plenum. However dodge no longer uses the rubber piece on the drain but thats not to say someone didn't install one or a mouse had got in and blocked the drain. You need to remove anything on the outside of the drain and try to clear the drain after which you should get a rush of water and debris. You can then reinstall or just leave it clear as dodge does now.
Congrats on the retirement, 7 years for me and I'm busier than ever makes me wonder how I ever had the time to do "stuff" before.

 

I should have kept my day job seems like I have more to do now than ever, the only thing different is I can take a break when and as long as I want. LanceD had suggested that I install a short piece of rubber hose and I recall seeing a similar suggestion over a year ago. Your information that the manufacture used to include them on earlier models seems to suggest that a longer drain helps. I used to work as a HVAC mechanic many years ago and understand the importance of a proper drain for the evaporator coil. Usually this is done with a P-trap to prevent the fan from sucking air up through the drain.
In an effort to show that I actually listen to advice I now have a piece of clear hose on the outlet that extends down under the truck and is tie-wrapped to the frame. I am in the process of evaluating how well it works.
If it fails or I still have a leak then it's open up the evaporator case and check it out from the inside. I think there is an internal trap inside the evaporator housing that may be plugging. I have been very reluctant to open it up for several reasons mainly the pain and discomfort of crawling under the dash and probably a couple visits to the Chiropractor after I do.
But you are right Busboy, the condensate level on the outside of the case is a good indicator of water level. I just can't see where it gets out and at time it's a lot of water. Destroyed my carpet and I am reluctant to replace the carpet until I'm sure the leak is stopped. I do appreciate your comments and the time you took to write them. Stay tuned I will post the end result of all this as soon as I have it whether it be a dead mouse, a fix, or me shooting my old friend "The Brute".

 

always try the easy fix first. I have a '98 that leaked into the passenger side floor. I bought a 2 foot section of heater hose and clamped it on the drain pipe that extends out of the firewall under the hood and routed it down and put zip ties on to hold it in place. No more leaks. very quick and cheap. I would try this before more complicated fixes. If you have the small metal (about 1 to 1 1/2 in ) tube extending out of the firewall and there is no hose attached, that is probably your problem. At least it was for me.