Cars - "Coolant Sensor Bad"

AutoBanter (http://www.autobanter.com/index.php)

- Jeep (http://www.autobanter.com/forumdisplay.php?f=14)

- - "Coolant Sensor Bad" (http://www.autobanter.com/showthread.php?t=73814)

"Coolant Sensor Bad"

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

"Coolant Sensor Bad"

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
>

"Coolant Sensor Bad"

> 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.

"Coolant Sensor Bad"

Have you tried unplugging the neg battery cable for 30 mins to re set the
computer?

Carl

> wrote in message
oups.com...
>> 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.
>

"Coolant Sensor Bad"

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?

"Coolant Sensor Bad"