Coolant light on dash

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Active Member
Jan 20, 2006
W124 300 E // W211 320 cdi
Hi folks
I have a w211, 320 cdi, 2007
Coolant low warning light issue, both sensors replaced on in the block and coolant tank, been told it could be a wiring issue..

If anyone can advise will be great
Other than checking what you can see visually a scan may show an open circuit somewhere, indicating a broken wire in a loom ?
Istr that for some reason some earlier Mercedes had the washer fluid light wired into the same circuit.
Could be worth checking out.
Some car manufacturers specify de-ionized water to be used
when mixing anti-freeze for the -40C or so lower temp requirement.

If the level sensor uses electrical conductivity, de-ionized ater
will not conduct the (very small) currents needed not to set the alarm.

Mercedes does specify that tap water is OK to use.
Warning is on all the time, thanks for the reply guys, will have a look into it, I may drain the water in the expansion tank and add deionised water with coolant, other than that most likely a wiring issue,

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