W218 CLS63S - coolant issue
SO recently iv encountered a problem with the coolant system on my car, below is a brief history of what has happened.
- I was driving on sports + and the coolant system had exploded so i pulled over and turned the car off immediately.
- The garage ive been taking it to for over 4 years diagnosed the problem as a leaking reservoir and leaking coolant hose which they replaced.
- I then received the car but this is where the problem arises.
- When running the car and the engine gets to temp the coolant goes all the way down triggering the check coolant warning.
- I then slowly turn the reservoir cap which then cause the coolant to come rushing back up to the point of initial filling.
Any advice would be really appreciative as i love the car and i've driven almost 130,000km on it taking great care.
Last edited by cls63sdxb; Mar 1, 2024 at 08:52 AM.




Use the vacuum refill method.
RTFM : do not open system at operating temperature... 200F degree burning hazard!
Last edited by CaliBenzDriver; Jul 28, 2025 at 02:55 PM.


