Coolant Level Sensor
 

I have had the "Check Coolant Level" light for the past month. I have bled the system as described in the Bentley, only to continue to have lights on shutdown. I searched my Bentley Manual for a description of where it is and how to replace it but my manual doesn't even mention it! What am I missing? (page #, please!) Or is it so obvious they don't bother with it. Thanks in advance for your help. I have a 98 e36 M3 vert.
jsm3

I'm about to replace mine for the same reason.

It is in the bottom of the expansion tank. The expansion tank is the milky plastic tank on the side of the radiator where you add the coolant. The float sensor screws on from the bottom.

Pelican sells two sensors for E36 and the desciption of the cheaper one says it fits the M3 but the part number is wrong. I bought the more expensive one ($25) because the part number was correct. You should probably buy a new o-ring while your at it. I think the o-ring was $3.75.

Replacement looks easy, but I'll know better in a week or so.

Fixed the discrepancies....

Does that mean I'll have to drain my coolant first if I replace it? BTW, someone on another forum mentioned pulling the wire plus from the sensor and spraying WD40 into it and then reattaching before replacing the sensor...
jsm3

I think it might be possible to get the existing sensor to work again. It is a simple design and could merely be stuck.

I think you will only drain the coolant from the expansion tank during replacement.

Jared, thanks for fixing the BW-61-31-1-384-739 part description. I called on it a few weeks ago but it was during a busy time and I didn't get through. I assume it takes a while for the change to take effect?

should refresh overnight...

I will do this Saturday and let you know how it goes.
jsm3

I can say from experience on my own car that the collant sender does indeed get stuck from time to time. I had to clean mine and free it up twice...

Jared, I was wondering why there is nothing in the Bentley Manual on this procedure, or am I just missing it?
puzzeled,
jsm3

There isnt anything in the bentley about it

The Bentley is missing many things, including this.

Basically, you remove it, clean the "track" along which the float travels, and put it back in the car...

Got it! I'll let you know how it goes after Sat.
jsm3

Please let us know if this works for you.

Ok, this morning I located the sensor. I was trying to get the wire plug off and it just will not budge. I bought a new sensor and some bmw coolant in case I needed them. The new sensor seems to have some "clip" doodads, (official BMW tech term), on the bottom but I can't get to the bottom of the sensor to see how to release it, (and I didn't want to force it), because the lower radiater hose is very close to the sensor and it looks like it will have to be removed to allow me to get to the bottom part of the plug and/or pull the sensor all the way out.

Is this what you had to do? About how much coolant will come out when I remove the hose? I know this stuff is bad and I will need to catch as much as I can. I just want to know what I am in for before unleashing a torrent of coolant.
Advice is appreciated.
jsm3

I think it will only dump the coolant from the expansion tank, but I don't know. Did you remove the slash gaurd from under the engine.? I think you should be able to see it from below with the splash gaurd removed. My splash gaurd is off I'll try to give it a look at lunch.

My lower radiator hose runs directly under the sensor. There is no way I can get the sensor out w/o removing the hose from what I see. Did you have this problem and have to remove the hose?
jsm3

I haven't done mine yet and didn't get a chance to look. If you pull the lower radiator hose you will definately dump a LOT of coolant.

Jared's done it, maybe he can answer your ?.

You should porbably change the coolant int he car anyway, considering it's probably full of phosphates, which may have caused the sensor to stick in the first place, if indeed the sensor is stuck and not faulty. Just be sure to bleed the system of all air afterwards.

The sensor connector has a lip that clips over the edge-->U have to pull up on the end away from you as you pull out
Usually kinda hard to get out without taking the Lwr hose off->>and alot of coolant will come out