Temp gauge not accurate.

[thebutcher37]

My temp gauge is not working correctly, it worked fine before my motor went kaput.
I turn on the car but don't start the motor and it goes directly to hot.....
Start the motor and the temp goes back down to cold...
after driving for a while it still stays cold while driving and doesn't warm up.
Until I stop, shut car off and it shoots to red hot and stays there.
it will stay for a while unless you tap on the gauge it goes back down.

Here's a video..


The car isn't overheating... I took out my cluster and replaced it with another known good working cluster and everything works fine, except the temp gauge, same problem persists so i know its not the gauge itself...

What should i do? what could it be?

[bmwguy325is]

The nuts on the back of the gauge like to fall off.

[thebutcher37]

The nuts on the back of the gauge like to fall off.

I added the video, its not the nuts on the back... I checked em and I also tried out another known good working cluster and same problem.

*also oil light stays on aswell...

[///digitalme]

temp sensor?

[thebutcher37]

temp sensor?

They are the same temp sensors from the first motor....

so it should be functioning the same... I think theres like 2 sensors right?

could they be switched around?

Does anyone know the orientation? color wise?
heres a pic for reference.

06 ENGINE COOLANT TEMP SENSOR 1-POL 1 12621710512 $25.78
08 Temperature sensor M12X1,5 1 13621709966 $37.35

I will def check the part #'s if possible ASAP...

[///digitalme]

the temp sensor under the throttle body could be your problem. There's a thread somewhere about someone had then switched. I would check my car but can't check since my car is at the body shop

[///digitalme]

Wait did you swap another engine??? I swapped another engine and my temp gauge was acting up until i changed my radiator sensor and temp sensor.

[thebutcher37]

Wait did you swap another engine??? I swapped another engine and my temp gauge was acting up until i changed my radiator sensor and temp sensor.

Yes, i got another m42 since mine bit the dust...

.. i guess thats where I'll start. radiator sensor (although that shouldn't have to do with the gauge inside)

I think its the sensors on the head. possibly wrong orientation... maybe the sensors aren't the original ones I had on before...