Yes, AC evaporator. It is VERY expensive to replace...about 16 hours labor, if I recall. The alternative, and the route I chose, is to use Cryoseal, a high-end sealant. Don't let people scare you away who say all sealants are snake oil. This stuff works well as long as the leak is not too large. See http://www.cryochem.com/r134a.php for details.

As to the chain, not sure what exactly the problem was and what the remedy is....others may chime in I think there was a TSB on it so may have been replaced under recall. Since it's an MB dealer that you're dealing with, they ought to be able to provide you with clear and definitive answers.

Just found details (copied from another post):

The "stretched" timing chains of 1993 engines are discussed in Mercedes-Benz Technical Service Bulletin Ref 05/91 dated December 1994. The heading says it applies to engines 602 and 603 in chasses 124 and 140, cars built between July 1992 and July 1993.
The bulletin indicates that affected engines may indicate one or more of the following: unusual noise form chain area, rough running, hard starting, loss of power, increase in oil consumption.

There is a list of specific chassis numbers in the bulletin. I have a copy I downloaded from Alldata. The chassis numbers are somewhat difficult to read but appear to be as follows:
For model 124, engine 602:
from B810470 to B999999
from D000001 to D025898
from J001335 to J01979
from F231885 to F266917
In the above list, the "D" could be a "C," it is very tough to tell.

for Model 140, engine 603
from A092142 to A155557

If in doubt, I would ask your MB dealer to check the bulletin for you.

The bulletin says that the chain should be replaced if the stretch exceeds 3 degrees. In that case, the timing chain sprocket is to be inspected. If the sprocket teeth are broken or worn as shown in the bulletin figures, the camshaft sprocket and injection pump timing sprocket are to be replaced. If the stretch exceeds 10 degrees, the pistons are to be inspected for damage.

The Bulletin does not indicate the warranty aspects of this. That is, it does not say who picks up the tab.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 160k miles
06 E320 CDI "Rutherford", Black on Tan, 180k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 79k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife