I was hoping that today was going to be somewhat warm. It was 48F this morning. I'm going to try the soap & water method for searching for the leak first. I also have a A/C detector dye that I can try. But how exactly do you detect a leak in the Evaporator? Just my eliminating all other possibilities I supposed?

 

The detector dye is good however it's very hard to spot on the inside of the condesor and obviously impossible for the evaporator. If you have a leak detecto(sniffer) you can turn the AC on and put the fans on low and stick the probe in the condensate drain and if you get a reading there, you have a leak somewhere in the heater/AC box. Really, there is only the evap and the lines going to the evap that can crack and leak. If you use the soap and water, you have to build up the pressure in the system 1st. Normally, if you have an obvious leak, you will see dirt built up at that obvious leak because there is refirgerant oil in the system. Normally when it leaks, it will leak oil and dirt will be attracted to it. That's one easy way to spot a leak.

I've tried the leak sealer in a can multiple times on mine and it doesn't work if you have more than a crack. The problem is, is that the pressure gets too high for that stuff to seal. It just blows it out. I actually just got my AC parts because my evap is leaking. If you do this job, be sure to replace your heater core as well while you are in there. It's a big job and the cost will be worth not to have to take the whole dash apart a 2nd time to do so. Plus, you need to recover the freon both times if doing them seperately.

Here is a quick view of the evap, heater core, orifice tube and accumulator for a reference.



This is the new evap but wanted to show you the lines on where they could crack and leak



If the evap is leaking it could also leak at one of the coils within the fins.
Again this is the new one going in to mine.

 

Oh, and if you need to do the AC Evap job, here is an awesome write up I found on directions to do it.

http://www.jeepforum.com/forum/f11/m...thread-592844/

 

Thanks Lyon. I had booked marked this link before. I got a whole folder dedicated to the Jeep

Got one more question. It has to do with the schrader valve. It either works or it doesn't? How do they diagnose it's a leak of the schrader valve? Just curious.

In case you have not noticed I am trying to avoid the evaporator fix by any means possible ..hehe

 

I don't blame you at all for hoping it's not the evap. I'm not looking forward to doing mine either.

The schrader valve just screws in to the port. You're right, it holds or it doesn't. You can do the spray test to see if it's leaking and use a schrader tool to see if it's loose and tighten it if necessary. Whatever you do, don't remove it or any part of the system with freon in it. You won't be happy.

Cool you had the link already. My favorites list on Internet Explorer is getting full. All you see is jeep jeep jeep jeep.

Any other questions that you have I will be glad to answer to try to help you out.

 

I have a 99 and the a/c cycles constantly. It cycles no matter where i have the controls. It never blows cold air though.. do you think one of these switches might be the cause of this?

 

This is normal. The compressor cycles to keep a constant pressure so you get the ac system does not blow up. It works just like an air compressor, if you just let it keep building pressure then (at some point) something has to give, so the compressor kicks on when the freon pressure is to low and kicks off when it is high enough. Nothing to worry about.