I have a 1993 300D 2.5L turbo. I have read that the W124 chassis has an achilles heal of evaporator problems and that it is a big cost repair. Just a simple question, does this problem just mean I won't have A/C when it fails or is there a bigger problem mandating a fix? Just wondering what to expect. Also maybe the above will answer this but how do I tell - no A/C in the summer or is there something more obvious to look for? Do the replacements if fixed appropriately by someone qualified also have problems? Thanks

1992-1995... W140 has the same problem -evaporator made from aluminum-copper and has tendency to corrode,for my S320 its $4000 to replace it.
Replacement is new version and made from different alloy so it should last much longer , if you gonna recharge freon ,add some dye and use UV light - inspect compressor,vents and clear that rubber hose (moisture relief from evap.)
it gets clogged with leafs and other crap from trees , so your evap isn't dry .its located near transmission drivers side...
BTW did you check your harness?If its 93 its probably falling apart......

To answer your question, you will just have no A/C cooling.

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Bill

Backyard Shadetree Mechanic, 30 years running.

1987 300TD
1988 300E (sold, sniff)
1999 S320
1981 Volkswagen Rabbit Truck (Diesel)
2001 Ford Expedition
1988 Suzuki Samurai
On my list to buy: R129, for me, and a R107 for my wife.

If you are a DIY'er, this job isn't too terribly bad to do yourself. I wouldn't want to do it again, but I replaced mine a couple of years ago and saved a bundle. The cost for repair isn't in the parts, it is in the labor you will pay a mechanic to do the repairs. I believe it took me right at 20 manhours to do this job myself.

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Mike

'80 300D
'84 300D
'85 300D
'87 300D

My evaporator was leaking. In part because of the expense, and in part because of the invasiveness of the procedure, I was very reluctant to replace it. So instead I tried a high-end sealant called Cryoseal (did a bunch of research, it seemed to be my best bet); web site is at http://ssrintl.com/.

After a year and a half, so far, so good...still blowing cold.

I know there are many who are very "anti-sealant" on this board. But, at least in my case, it's worked well and saved me a lot of money.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Chryoseal will work IF the leak is not too large. In the case of our 95 E320 wagon, it was not a candidate for the treatment, although I've heard of others who are still going several years after the "fix".

You have to have an authorized installer do the job, they will only sell the product to a shop, so that will increase costs somewhat.

For me, I started on a Monday, worked a fair amount on it the following weekend, and had it buttoned up by midweek. Didn't total the hours, but I'm sure it was over 20....

Cost was around $600, but I did all the vacuum pots as well.

Jim

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles