My 2015 Forester MBS is 32 months old and just hit 49,000 miles. It has never lost one drop of coolant, so I was quite surprised to see the low coolant icon on the dash light up on a recent trip. (Can't miss it, it looks just like a radiator).
I popped the hood and found the plastic coolant recovery tank below the "MIN" mark for the first time ever. I then noticed a small drip, but couldn't tell where it was coming from.
Since Mercedes stupidly did not include a temperature gauge, I connected my Scantool device to read my coolant temp. It was a perfect 209 degrees, so all was well inside the engine. Thank goodness!
The next hour was spent figuring out what type of coolant MB demanded for this model, and finding a radiator shop in Bishop, CA. Once a pressure tester was connected, the mechanic laid on the ground and looked up with a bright flashlight and found the leak.
The coolant hose that RETURNS coolant to the reservoir had pooped out of it's holder on the top of the fan shroud and had been hit by the fan. (No, I did not hear it happen). It made a small gouge and small leak in this hose. He cut out the damaged section and installed a metal hose barb splice. Good as new!
Then we topped off the coolant and installed a cable tie in the hose holder so that it can never pop out again. I HIGHLY RECOMMEND that every MBS owner do the same. It only takes 30 seconds and you can do it yourself. It will prevent the incident that happened to me. Photos are attached. (The white residue is dried coolant that was spun by the fan).
FYI: I also suggest that you use your owner's manual now to figure out what type is correct for your MBS. Then carry some just in case. It was very confusing deciding which one was right. There are at least seven colors of coolant nowadays!
https://www.valvoline.com/our-produc...engine-coolant