I have searched up and down the interweb an cannot seem to find another example of the issue I seem to be having.
The basics
2002 C32 Amg with about 98,000 miles
I'm getting an error message that reads coolant visit workshop it comes on for a second, then goes away then comes back, etc. I have also noticed as soon as this happens my A/C doesn't blow as cold as it did moments before the message. Now I have checked both my coolant res and my wiper fluid res. Both are fine. I have metered the sensors for each and they read correctly as well. Now my car has never overheated. I'm in Texas with temps from 80-100 outside. The car temp starts low, then rises to 85-95 with a little fluctuation here and there. This leads me to believe the coolant temp sensor is fine as well. Because the car does get up to temp, I know the thermostat is not stuck open.. And I doubt it stuck shut, as temperatures appear normal. Now when I start my A/C (before the message) the single cooling fan, radiator fan, suction fan, whatever you chose to call it, comes on as normal. As soon as the fan goes off, that's when it appears the warning on the dash flashes. I have pulled over multiple times to check as soon as the light comes on, and the fan has always been off. It appears as if the fan isn't working correctly consistently. It's not in high speed mode, no fuse seems to be blown, it just seems to only work for the A/C and not for the engine.. My question here, before I go funning to the dealership and admit defeat, is does anyone here have any info on this exact problem? The wire harness appears to be fine, as I said the fan isn't in super high protection mode.. I'm assuming its the fan computer, but any help at all would be appreciated.. Thanks for taking the time to read this novel..

 

I came across your post while recently experiencing the same issue on my 2004 with 60,000 miles. In my situation it seems like my fan is not turning on at all, even when A/C is switched on. I just brought it in to the shop, but curious as to what your problem was and your solution?

Thanks

 

I'm sorry to say I never found a fix. I took it to my local stealership after trying everything I could think of and they couldn't find a fix either. I eventually just broke down and traded up to an 06 E55. Again, sorry I can't be of much help, but I hope you have better luck than I did.

 

did you check the codes? It could be your thermostat went bad (just means its staying open and coolant is continuously flowing which lets face it isn't terrible unless you live in the fridge and want the heater to work, lol). Check the engine codes. When mine failed in my C230 the temp looked just fine as well, but as soon as I check the codes thats what it told me. Once I replaced it, the error went away and the CEL.

 

Thanks for the replies guys.

I won't rule out the thermostat possibility. However, the vehicle warms up properly in cool weather.
The coolant temperature started to rise on the first warm day when stopped or in slow moving traffic. The fan would not run when warm and idling. It also would not run when the AC is turned on.

I will check the codes and be sure to let you know when I find a solution.