Hello gents, I've got to replace the AC compressor on the wife's '98 C280. The compressor seized (the shop tells us) so we got a new one. Shop wanted 1500 clams but parts (compressor and drier) were $500, and I'm looking to DIY. The job does not look difficult but there are accesss issues for my big hands. Three bolts on the compressor, two allen bolts holding the hoses. I have done all my BMW work, but those are older cars without the cramped quarters of the C280; also worked on older MB some with the neighbor.

Have done an hour-plus of searching but nothing seems to come up. With the issues this car has had, I don't think I'm alone.

First question: do I try to get a shop to recover the refrigerant first, rather than simply venting it? I know I'll have to get a shop to evacuate and recharge later.

Second question: not being familiar with this engine and the serpentine belt, where/how do I release tension to get that belt off?

Thanks!

You need to flush the system with a good AC flush fluid and purge all of that flush fluid with a lot of dry compressed air (or better yet, nitrogen). Failing compressors will fill the system with fine debris for a long time before they seize, and you need to get that out.

I would recommend replacing the condenser, as these are very hard to flush and even harder to purge. Also replace the expansion valve, which must be removed to flush the evaporator anyway.

I would certainly get a shop to recover the existing refrigerant. However, once you uncap the new dryer, you need to add oil, connect it and immediately vacuum the system. I would be hesitant to connect it and then drive to a shop for evacuation.

I have heard that Autozone has a tool rental program and some locations have gauges and vacuum pumps. So you could vacuum and refill yourself. I just completed doing a 240D, and it was a relatively easy project (although time consuming, but then again I didn't have to change out the condenser or evaporator.

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1976 240D
1987 560SL
2007 E320 Bluetec
1998 C280 (now son’s car)
1982 240D Manual - Sold

thanks for that note.

I have access to my neighbor's vacuum pump and he has a set of gages, plus the PAG oil. We've done several refills on his older (mid 80s) Benzes, though he has no scale so he refills until the pressure comes up about right.

Guess we can do the same for the C280, just need to get on schedule with it. There goes half the weekend, at least. Well the wifely unit will scream until it's done, so off I go.