check coolant level light - only when outside temp is really cold. Normal?
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Junior Member
Joined: Feb 2025
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2017 C63s converitble
check coolant level light - only when outside temp is really cold. Normal?
lately, when ive been cold starting the car on days when its really cold outside, the car will tell me to check coolant levels. No red light, just amber. operating temps seem normal. level seems normal.
Only happens when the car has been sitting for a day, and the garage is kinda cold (40ish degrees)
wanted to check if this is a normal message that comes up....or if a sensor is starting to go bad
Only happens when the car has been sitting for a day, and the garage is kinda cold (40ish degrees)
wanted to check if this is a normal message that comes up....or if a sensor is starting to go bad
MBWorld Fanatic!
Joined: Jun 2021
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From: Fleriduh
W212 E63S Wagon - GSL580 - E63 - E350 - C300
Very very common. Few weeks ago it got cool and I had three of my cars do that....the first one was a couple days after I put a new radiator in the E63....then the GLS did it...then the other E did it....
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From: Keep it simple - keep it OEM
AMG C63s Coupe
Out Of Control!!
Joined: Nov 2018
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From: San Francisco Bay Area
2019 C63CS
Well, check the level. That will tell you if it's actually low or if the sensor is on the fritz. Like most substances, water contracts as it gets colder, meaning it gets denser and the volume decreases. In case of water, that happens until it reaches 4C, at which point it starts expanding again as it gets colder due to the ice crystals and finally solid ice which is less dense than liquid water. So when it gets cold, the level can fall below the min marking. The min marking is also known as the cold fill. The level should be at min when the engine is cold, so in your case when it's 40F outside or lower. The max marking is known as the hot max. As your engine heats up, the coolant expands and it should not go above the max level, so basically it should always be between min and max at any temperature.
