The girl that owned the WJ before me allowed her quickie-lube to add
Prestone Universal (DexCool) to the system.

It turned the coolant into brownish red sludge

The sensor is pretty much a float but the float gets stuck when it is full
of sludge.


"Lon" > wrote in message
. ..
> proclaimed:
>
>>>IS there a layer of brownish red scum (or any other color) in the
>>>expansion
>>>tank?
>>
>>
>> No, but there was back when I bought the car. I flushed the coolant
>> using one of those garden-hose adapter things, and cleaned the overflow
>> tank about two years ago. I wouldn't eat off of it or anything now, but
>> it's reasonably clean.
>>
>
> Connectors on the wiring to that sensor all crudded up?