Water Wetter
Super Member
Joined: Dec 2004
Posts: 714
Likes: 17
From: CA
C63
In my experience of owning Mercedes and even with the M156 engine, overheating inst really the problem. I believe Merc engineered a pretty robust coolant system. On the other hand, oil cooling and tranny cooling are more of an issue. Not sure you want to waste money on Water Wetter/
MBWorld Fanatic!
Joined: Jun 2008
Posts: 8,074
Likes: 2,867
From: Los Angeles
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
It’s not a waste. It works. And it’s good for the cooling system whether the car overheats or not because of the surfactant effect and heat transfer properties. Your loss for not splurging the $12 for a bottle. Well worth it. Especially on a car that runs hot. 
