That is a BIG job on the W140 platform since the car was basically built around the evaporator.

Steve Brotherton did an Excellent write-up on the subject here:

http://www.continentalimports.com/ser_ic40142.html

Good luck.

__________________
"It's not about how fast you can go, but how well you can go fast."

Bob in Richmond

'97 S320 (LWB), Ruby Red Metallic, 73k miles
'97 S420V, Smoke Silver Metallic, 155k miles