Have a 2014 ML 550 55k miles that has started displaying the yellow "check coolant" message. Upon checking coolant it looks fine, had it in to check, shop says they found a leak, replaced that did a flush etc... few days later message pops back up. I am not seeing any leaks on the ground or even inside. The message would first come up when I started after sitting for awhile or overnight, temps did just drop a little here around 40s, some 30s. Today for the first time it came on while driving, at the same time I noticed my temp gauge dropped from its normal 90-ish down to 80 and hovered there for maybe a min then went back to its normal range, and the message went away. It did this twice about 15 mins apart, continued to drive and didn't see it again. Went to start up again, instead of clearing like I usually do, I let it stay to see if it would clear itself, as soon as the temp gauge reached that normal temp it went away. I say all that to say, could this be something other than a leak? A sensor of some sort somewhere, something connected to the temp gauge?
I didn't find the right solution from the internet.
http://www.benzworld.org/forum [...] ction.html