R&R 300e evaporator
 

My wife's '93 300e has been diagnosed with a leaky evaporator by using a dye in the refrigerant.

My questions are: How reliable is the dye method of leak detection. Has anyone done this job and how difficult is it. I have restored collector cars and rebuilt engines and transmissions but have never messed with A/C.

Thanks to all who respond
Joe

I am a DIY'er and I did it with the factory manuals. It took me about a week of PAINFUL work. If you enjoy working on cars, have the manuals and the time, it is "doable". If you don't, pay somebody to do it. It is expensive. Whatever you decide, get a copper core evaporator.
As far as the dye, that is how they found mine leak. Very reliable.
Do a search on the subject, right upper corner of this screen.

Evaporator leak
 

I had a similar problem in my 1990 300CE. There is an additive made by Cryo Seal. It works great for small leaks. I have had it my system for 3 years, no leaks.
If the leak is too large than it will not work.

Their web site is:
http://www.cryochem.com/