124 Evaporator Symptoms - PeachParts Mercedes-Benz Forum

thayer · #1 10-03-2010, 09:12 AM

OK....so, my newly acquired wagon has a functioning AC. I have read many posts on the evap leaking. I wanted to hear from those of you with a 124 that had a leaking evap and see what the symptoms were.

When I added just one can of 134 yesterday I got working AC, but the freon was obviously low as I had to jump the low pressure switch. I'll check it again in a week and see if I still have air. (it is patiently waiting for its transmissionectomy).

So, fellow 124 people, is there anything else I should check/be thinking about regarding the AC?

Matt L · #2 10-03-2010, 11:13 AM

The symptoms are the same as for any other refrigerant leak.

M-B has a tool which bolts in place of the TXV, allowing the evaporator to be isolated and pressurized with nitrogen. This is a definitive leak test.

sixto · #3 10-03-2010, 02:15 PM

You can add dye to the refrigerant charge to look for a leak. Prior to that, though, you have to suspect a leak. Look for decreasing static pressure over time.

Sixto
87 300D

bobodaclown · #4 10-03-2010, 04:26 PM

If it's the evap that sucks because you have to pull the dash. I've got a sloooow leak in mine. Pressure drops in the system or system doesn't cool when it should. By slow I need to add top off my system once or twice a season. Once at the beginning and once mid-way through. Get a few cans on sale $5 or full price of $9. 15 minutes or so to top off the system. Beats the trouble of pulling the dash. When the leak gets too bad I'll bite the bullet.

shertex · #5 10-03-2010, 05:41 PM

FYI I successfully sealed the evaporator leak on my 92 300D with Cryoseal (a high-end sealant). I did a lot of research on the stuff http://www.cryochem.com/r134a.php. From what I understand, evaporator replacement is a solid 16 hours of labor...just couldn't see spending that kind of money.

Now I've got a leaking compressor (Cryoseal does nothing for compressor shaft seals), so I'll need to replace at some point.

Matt L · #6 10-03-2010, 05:48 PM

That Cryoseal is going to love it when you open up the system to replace the compressor. Good luck.

shertex · #7 10-03-2010, 05:56 PM

Quote:

Originally Posted by Matt L

That Cryoseal is going to love it when you open up the system to replace the compressor. Good luck.

While I lose the benefit of whatever sealing the Cryoseal might have done with respect to new leaks, it sealed the evaporator leaks at the time. I'm fine with that. It's been in there a good four years.

Matt L · #8 10-03-2010, 06:13 PM

Quote:

Originally Posted by shertex

While I lose the benefit of whatever sealing the Cryoseal might have done with respect to new leaks, it sealed the evaporator leaks at the time. I'm fine with that. It's been in there a good four years.

I'm talking about anything still in there, that will harden when air hits it.

shertex · #9 10-03-2010, 06:17 PM

Quote:

Originally Posted by Matt L

I'm talking about anything still in there, that will harden when air hits it.

Maybe pulled out beforehand?

From FAQ

Q. Will your SSR R-134a or R-22 sealants and dehydrants have any effects on my Recovery and Recycling equipment?
A. No. When a refrigerant charge containing our products is processed through recovery-recycling equipment, our SSR products will separate out with the refrigerant oil early in the reclaim process. Also, as long as your machines filter-drier has been maintained and is not contaminated (full of moisture), our sealants WILL NOT harm your equipment. This was tested over 40 years ago during our Research and Development period. There will not be any deleterious effects on your recovery-recycling equipment.

bobodaclown · #10 10-03-2010, 06:43 PM

This Cryoseal stuff sounds interesting. Any others have any luck with it?

Did an archives search. Back in 2000 there were some interesting posts.

thayer · #11 10-03-2010, 08:12 PM

If I find a leak in the evap I will be at least trying the cryo-snake oil. take the evap out...."I can't want to" as my two year old would say.

give it up for four years! any ac repair that lasts 4 years should be considered a worthy repair, especially on these benzes. I'm coming into the 124 world from the land of r4 comps which are like taxes...once or twice a year, go pay homage to the r4 throne.

And besides, if it doesn't work whats the worst I will have to do? take the evap out and flush the system.

After we added the one can of 134 it wasn't enough to overcome the low pressure switch so I went and got some more. I'll put that in tomorrow and see if it comes up to pressure.

I just took the wagon out for a 20mile excursion/tranny test. We put two bottles of Lucas slip stop into a severely slipping/flaring tranny and now it seems to be running fine. some of the shifts are hard, but we were also playing with the modulator. I will need to drive it more to see if I can't pull some use out of it before the rebuild.

vstech · #12 10-04-2010, 08:55 AM

Be sure and warn me if you use cryoseal in there!

thayer · #13 10-04-2010, 10:09 AM

Yeah well...what I was thinking was to evacuate the system by unplugging a schrader valve, washing the whole thing out with a water hose, fill it with cryoseal and propane and start smoking everytime I get in the car.

vstech · #14 10-04-2010, 10:10 AM

Quote:

Originally Posted by thayer

Yeah well...what I was thinking was to evacuate the system by unplugging a schrader valve, washing the whole thing out with a water hose, fill it with cryoseal and propane and start smoking everytime I get in the car.

thayer · #15 10-11-2010, 08:33 PM

well...the evap does have a terrible leak. I filled it up with 134 and it blew 38 - 40 for about 20 minutes....turned it off, then back on again after about 6 seconds and I think I inhaled about half a can of 134. Oh well.

anybody feel like taking my dash apart for me?