I replaced a leaky a/c hose in a friend's 97 E320 - it was a massive leak. The system calls for 33.5 oz of R134a. After vacuuming for 2 hours I only have 2 cans in there now (24 oz.) and the high pressure is already over 400psi. I found the problem: the aux fan is not kicking in at all. Ever. I watched the gauge start climbing towards 425 and no fan, so I shut it off.

I'm guessing the old hose sprung a leak due to excessive pressures when idling.

I did a search, and there is plenty on the W124, but I can't find much of anything on the W210 aux fan. Where do I start?

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280