A/C system--sanity check please? - PeachParts Mercedes-Benz Forum

bsharp8256 · #1 06-01-2021, 05:54 PM

Hi all, my 99 E300 lost AC last fall and being the type of person I am, I put it off until it got warm again. I believe that the reason it went was overpressure. On hot days my car's coolant temp goes up to the 100C range when not moving, and I believe that's due to a failing fan clutch which will also be getting replaced in this round of repairs. I've never repaired AC before so I'd like to do a sanity check before ordering parts. Here's the codes I've pulled from the HVAC module:

B1227 Outside temperature indicator temperature sensor
B1235 Emissions sensor
B1241 Refrigerant fill
B1419 Electromagnetic clutch

It failed last Sept/Oct when idling in a parking lot on a 90F+ day and given the compressor clutch went and it's calling for more refrigerant, my guess is the entire compressor should just be replaced. If this is the case, I'd also be replacing the reciever/drier, expansion valve, and doing a flush on the system.

Is there anything else I should replace while I'm in there? Hoses? Condenser? (Please don't say evaporator

)

A/C gurus, please let me know if my line of thinking makes sense!

tjts1 · #2 06-01-2021, 07:49 PM

First read the codes stored in the w210 climate control.
https://youtu.be/sxMgM6Oj8IY
Before buying any parts, check the continuity of the clutch coil. The w210 AC clutch coil has a thermal fuse built into it. When the clutch coil gets too hot the fuse blows and it stops working permanently. It's common for the thermal fuse to blow for no reason other than being old. The same Denso AC compressor was used on millions of Toyotas without a thermal fuse. If the clutch coil has no continuity you can just replace the coil with a Toyota item. I went through this **** with my 97 E300 at 225k miles. Replaced the clutch coil and it's been going fine ever since.

jay_bob · #3 06-02-2021, 07:42 AM

Went through this in 2016. W210 compressor seized

Check the hub on the compressor (the center part) with the engine stopped. See if you can spin it with your hand (clockwise). If it is stuck then the compressor is gone and a clutch coil isn’t going to help you.

I stripped it out completely and the ac was still strong as ever when I sold the car in 2019.

bsharp8256 · #4 06-02-2021, 08:48 AM

Thanks to you both for the input, I'll drag the car into the garage this afternoon to check both the coil continuity and see if the compressor seized! I still haven't ordered parts since I work from home and don't drive much anymore. I can suffer for a bit to ensure I get things right the first time!