IS there a layer of brownish red scum (or any other color) in the expansion
tank?

> wrote in message
ups.com...
> Hi All,
>
> I have a 1997 Jeep Grand Cherokee Laredo 4x4. For the last year or so,
> every so often (a few times a week), I get the message "Coolant Sensor
> Bad" in the center console (the area that shows "miles to service" and
> when doors are open and such). According to various sources, the
> coolant sensor in question is the coolant level sensor in the overflow
> tank. The other coolant sensor that is in the engine block throws a
> "check engine light" error code if it's having problems (I've verified
> that by unplugging it), so I'm reasonably certain that that's not the
> one causing the problem.
>
> Now, I'm sure most of you are thinking, "why don't you just replace the
> coolant level sensor?" I did that right away last year when it first
> started happening. It didn't have any affect on the problem whatsoever.
> I've also brought the car to the Jeep dealer, and surprise, surprise,
> it didn't happen while the car was there, so I got to pay the
> diagnostic fee and go home.
>
> One interesting thing is that the "coolant sensor bad" message didn't
> occur all winter, so it does appear to be affected--at least to some
> degree--by temperature.
>
> Anybody have any ideas on how either to fix the problem with the
> coolant sensor, or to at least get it to stop telling me about it? I
> don't particularly care if there's a problem with the coolant level
> sensor...I'm perfectly capable of lifting the hood to look at the
> overflow tank, but the beeping from the console is kind of annoying.
>
> Thanks,
> Tom
>