COOLANT FULL
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Member
Joined: Feb 2016
Posts: 83
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From: DFW
2006 C230 with 139k and 2005 C240 4matic
COOLANT FULL
The engine fan turns on extremely fast and loud seconds after starting the car; the display indicates check coolant; the coolant over flow reservoir is full. Is it possible the coolant sensor is the problem or the ECU?
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Joined: Dec 2003
Posts: 3,276
Likes: 236
From: BC, Canada
2003 C230K Coupe Orion Blue
Quite possible the coolant sensor is the issue, but I would also look into a few things to help diagnose it.
a) Is your coolant at the correct level? For the W203 it should be at the top of the clear part of the tank when the engine is cold.
b) What's the indicated (in the instrument cluster) coolant temperature when you first start the car and the fan goes haywire? When the cluster shows Check Coolant, is it asking you to check the level, or something else? (I've only personally seen the Check Level warning)
Hopefully the problem can be traced to a bad coolant temperature sensor. That thing is a 2 minute job and doesn't even require tools.
a) Is your coolant at the correct level? For the W203 it should be at the top of the clear part of the tank when the engine is cold.
b) What's the indicated (in the instrument cluster) coolant temperature when you first start the car and the fan goes haywire? When the cluster shows Check Coolant, is it asking you to check the level, or something else? (I've only personally seen the Check Level warning)
Hopefully the problem can be traced to a bad coolant temperature sensor. That thing is a 2 minute job and doesn't even require tools.
