mis3

It happened twice in a week that when I started my car in the morning, there was malfunction "Check Coolant Level". I then restarted the car and the mail function went away. I checked the coolant level and it was more than half full in the tank. The car did it overheat..p

Is this a possible sensor issue? Where is this sensor?

DanielFD

half full will trip the sensor did u fill it up?

mis3

I checked when the engine was cold. Isn't half full OK ?

DanielFD

actually full would be all the way up, right where the black plastic begins(if your looking from the side)

Yidney

Been a while since I've looked, but isn't there a line on the reservoir to tell you where to fill it to? Usually there is. But yes, the sensor will trip if it is low even if it has quite a bit in it. Any car will.

Yidney

And if the level is right where it will trip, it will go off as the car warms up because the coolant expands.

mis3

I came home and checked the coolant level after 10minutes of engine shutdown. The coolant level is about 3/4 and I did not see any min/max markings on the coolant reservoir.

I can get some MB coolant this weekend. Should I fill it to the top? To add this small amount of coolant, maybe I do not have to dilute it with distilled water.

mis3

I passed by the dealership and they just added the coolant for me. It was a 15-20 minutes drive so the car was somewhat hot.

They guy just did it outside in the service parking. He opened the reservoir cap slowly and added the premixed coolant (red) all the way to the top. He left the cap off, started the car and left the car to idle for about 5 minutes. He then closed the cap, wiped down the side and I was on my way. He told me that he let the car idle for a few minutes so the overage would spill out.

FFXF1

On my 2006 W209 CLK there is a plastic tab that sits right in the middle of the filler neck, about an inch beneath the opening. Fill level is even with top of the tab.