Leaking 500E evaporator
 

After reading the search results in this excellent forum, I am leaning towards trying an a/c sealant as described in the Cool Profits magazine article that one of the forum members linked us to. However, I would be interested in feedback from shops that actually tried this admittedly band-aid solution. My shop quoted me a down time of 3 to 4 days and a lot of money... The system holds the charge for about 10 days, so I hope that the leak is small enough to be patched up by the sealant.

TIA for your replys!!

Wolfgang

I have never personnnaly tried the sealant solution but my brother did in his 1993 400E. A few weeks later, he had the ''big jobe'' done as the sealant did not really improve things that much.
he was charged for 20 hours of labour, plus parts.
Hope it works for you
JackD

On the 500E, I would charge about 15 hours labor.

The sealant has ruined many cars....I have personally had to do an insurance job on one because the sealant stopped up every component.

Thank you for your replies. That is pretty much what my shop warned me about. What sealants have you tried (I guess there are three or four manufacturers that offer them) or did you have bad experiences with all of them?

I was planning to get the evaporator replaced anyway, just not right now. The 500E is my daily driver and this is the first time it will be down for more than one day. It has been flawless in performance and reliability so far (126000 miles). I hope this is not a sign of things to come...

I remember some sealant that used to be out there (probably still is) they said it will stop evaporators from leaking . lol , We had a customer have us try it even after our warnings , (car was a 93 500 Sl 129 body ) anyways we put this stuff in and it clogged up the expansion valve , and had nothing but problems.
Needless to say we ended up replacing evaporator , expansion valve , reciever drier and flushing complete system due to contamination of this good for nothing @3*&$ . As you can tell the customer got a heavy bill and we got alot of headaches from flushing this car. The customer would have saved money just doing the evaporator and wouldnt have paid 2-3 xtra hours for disconnecting all lines and removing compressor for a flush. Evaporator on your car is right at 15hrs or so depending on your location. Have them replace all the vacuum servos while they are in there, you will thank me later. Good luck:D

euro287,
Thanks for sharing your experience with that sealant. Do you remember the name of it? Are there any differences between the products offered for this purpose?
I have gotten less response to my post than I expected and the feedback has been negative....
Anybody out there who had success with patching up an a/c leak with a sealant?

Thanks again for your replies!!!

Wolfgang

OK, I'll toss out a success story. I used it to fix an evaporator leak on my 1987 124 wagon. Car had a two-month kind of leak - a/c would work fine for one month, barely cool for a second month, and was after that essentially useless.

I used the cryo-chem brand sealant. Worked perfectly. A little bit of inital leakage while it did its job, then perfect. System cooled great all through our Texas summer.

About a year after installing the sealant the front seal on the (old, remanufactured) compressor failed, dumping the oil and refrigerant charge. The failure did not cause any problems with the sealant.

It is very important the system be thoroughly dehydrated when using one of these sealers - they are moisture activated. Perhaps the problems seen by techs here occurs when the sealer is installed into an R-134a system filled with "wet" PAG oil. (PAG oil is extremely hygroscopic.) In my case my R-12 system was filled with mineral oil - much easier to eliminate moisture.

My system is currently back up & running just fine, but without sealer. I had to disassemble & flush because it suffered the "black death" when the compressor failed. I did not see any signs of the sealer inadvertently activating inside the system.

I hate to put my name to this but I have watched this discussion at many different technical levels. Anyone putting his name on quality work will hide their head on this subject. With that said, I do have a positive experience. My tightwad German partner heard me discussing the scientific principles on this subject and decided to try it on his 93 400SE. It was leaking a pound a month last summer and he put the stuff in and has yet to add any refrigerant. I hate to say, how well it it working.

We have not done this on a customers car and probably won't unless they bring up the subject. There is numerous questions about what the stuff will do. The way the product works I know a little about. Interestingly enough the basic chemical is manufacturered here in Gainesville and there has been two toxic spills at the facility that have had wide spread media review. The chemical a hydrate of silicon I think forms silicon dioxide crystals in the presence of water vapor. Thus in the spills there were huge white clouds of sand so to speak. This is what plugs the hole as the product reaches the moisture in the air. I would say that systems contaminated with moisture would really take a beating.

It will never go in any car I own.

Dang, Steve! You got his hopes up and then shot him in the heart!!:D

Right through the heart...

Anyway, more negative, doubtful and "maybe" opinions than positive ones.

Car is going in the shop to be repaired properly!

Thank you for shedding a little light on this subject and helping me confirm what I thought anyway. At first, it sounded tempting to patch it up and get it repaired later...

Thanks again to everybody that took the time to respond!

Wolfgang

Good luck! You're doing the right thing. Do it right and do it once and you'll have piece of mind. They will undoubtedly use an all-copper evaporator so it should last for the life of the car.

I like the idea of replacing the vacuum elements while the dash is apart. The tech that replaced my evaporator didn't do this and I have a vacuum actuator which intermittanly makes a "moaning" sound while idling. System works fine but it IS irritating!

Truth be told, I think the repair depends on the owner and the car. With an E500, I would not attempt an unkown repair. If it was a 1986 300E with a bajillion miles, I'd be tempted to try the sealant and just hope for the best. Knowing me and my finickity nature with cars, I'd replace the unit, but I would understand someone with a car worth $3500 to try an economical repair...

Yes the name of the sealant was cryo seal. There is an old saying (you get what you pay for) and that customer did.:D

I would not even have thought about getting it repaired properly, if the repair would be easier. I was a little concerned about the scope of this adventure...removing the dashboard, removing airbags, switches, handles, steering wheels, instruments, vents, etc, etc...
The more you have to disassemble, the bigger the possibility of it not going back together the way it was and causing related repairs and so on...
Luckily, "my shop"(Hi-Line Mercedes in Orange, CA) has been excellent in every regard so far!!

Thanks again for all your input.

Wolfgang