[SewerRanger]

I keep getting a semi random notice that my coolant levels are low, but I've checked and they're fine (even added some more to be certain - more then half the reservoir is filled) so I'm guessing the sensor is bad but I'll be dammed if I can find anything about a replacement sensor. What am I missing here?

[jzeiler4]

I looked as well for the 240 and there is no sensor listed on my reservoir either. Looking forward to the answer on this.

[freakystyly]

There has been a couple threads on the F30 side stating that it is built inside the expansion tank. So you potentially need to replace the tank.

I'm not 100% sure if the above is true. But try to broaden your search to the 3 series side of the forum if you can't find answers here.

[XutvJet]

The sensor is embedded into the plastic of the reservoir and there is a connector that plugs into reservoir housing. Look at the photos in the link and you'll see what I'm talking about.

https://www.ecstuning.com/b-bavarian...IaAh_hEALw_wcB

[SewerRanger]

Originally Posted by XutvJet

The sensor is embedded into the plastic of the reservoir and there is a connector that plugs into reservoir housing. Look at the photos in the link and you'll see what I'm talking about.

https://www.ecstuning.com/b-bavarian...IaAh_hEALw_wcB

Oh yeah, I can see it on like the third or fourth photo. You wouldn't happen to have a link to a video showing it being replaced would you? Can't seem to find any for my car. Doesn't seem hard to do, but I like to know what I'm getting in to before I start

[jzeiler4]

Checked out that site for the M240 and see the connector also built into the tank.

[SewerRanger]

Originally Posted by jzeiler4

Checked out that site for the M240 and see the connector also built into the tank.

I don't get why wouldn't they just include that as a part of the description for the tank. Something like "Plastic coolant expansion tank with coolant level sensor built in" or something along those lines. It would save a lot of confusion

[XutvJet]

Originally Posted by SewerRanger

Oh yeah, I can see it on like the third or fourth photo. You wouldn't happen to have a link to a video showing it being replaced would you? Can't seem to find any for my car. Doesn't seem hard to do, but I like to know what I'm getting in to before I start

It's not hard to remove the coolant reservoir. I can't find any video's, but per RealOEM website and looking at my M235, it's only held in with a 8mm screw and then lifts out. With the cap and overflow line still connected, remove the temp sensor connector. Next remove the coolant overflow line by simply taking a pick tool and releasing the metal securing clip on line connector to the reservoir by lifting up. You then pull the coolant overflow line off the reservoir. If the line is stuck, twist it slightly and pull. If that doesn't do it, carefully pry/push it off with flat blade screwdriver. Next replace with the new reservoir, insert the connector and coolant overflow line and fill up the reservoir to close to the max line using the coolant from your old reservoir.
You don't need to worry about purging the system.