coolant low sensor

[flagstaff]

ok, so just changed the coolant on my '91 230TE. went well, flushed engine and reverse-flushed radiator. everything fine except that since the change, the coolant low light on the dashboard remains on ... coolant level is fine. anyone any idea what might be causing this?

 

[justin1820]

the float level switch in the coolant reservior hasnt returned because of dirt on top of it, it needs taking out and cleaning, it will be as good as new

 

[flagstaff]

thanks Justin - sounds reasonable! will investigate

 

[flagstaff]

excellent tip justin - you were right. sensor all crudded up. removed sensor float and cleaned, sluiced the whole header tank out ... now all back operational again. cheers!

 

[johnrr]

coolant level switch

A word of warning to anyone planning to replace a coolant level switch on a W124. Stick to the genuine MB part (there's only a couple of quid in it) the ones sold by a very well known pattern part supplier don't seem to work properly in the header tanks on 124's. On some of these non-genuine sensors the float has to drop almost to vertical to bring on the warning lamp. On the 124, at least the late models, the float will contact the bottom of the tank before resistance in the sensor is low enough to operate the warning lamp, so you'll be in blissful ignorance till your motor loses lots of water and overheats!

 

[Geoff_Slade]

Wish I'd known that! I had the same problem and topped up even though the coolant was between minimum and maximum. What's the procedure for removing the sensor and cleaning the float as it sounds like a worthwhile job?

 

[LNM]

First off, go and get a pair of circlip pliers. You might _just_ get it the circlip off, but you'll be in tears before it goes back on again without them.

(bitter, bitter experience)

remove circlip, pull sensor out, clean crap off it, replace and top up coolant.

 

[Geoff_Slade]

Cheers. I'll wait for the warmer weather and have a go (everything all right with the dashboard light at present).

 

[nickerina]

Coolant Light - will not go out

I have a ml320 1999 - and I am having trouble with the coolant light also. It is full, the light will not go out. I read the solution regarding the sensor - is it easy to find when you unscrew the cap? (sorry for the silly question)