Bimmerfest - BMW Forums

Bimmerfest - BMW Forums (
-   E36 (1991 - 1999) (
-   -   coolant gauge issues (

jccny13 11-16-2012 10:53 AM

coolant gauge issues
Hello everyone. Brand new here, but just purchased my first 3 series.
1995 convert.
When I purchased vehicle coolant gauge stayed in cold position at all times.

Replaced coolant gauge sensor last night:

As soon as it was installed and I clicked engine over, temp gauge went pretty fast right up to hot and the warning light came on (about 15 seconds)

Coolant was room temperature and was not hot.

This morning, after the car cooled all night, the temp gauge started at normal and immediately went up to hot.

I did disconnect the wire harness and the gauge did go back down to cold.

Is this problem an issue with the gauge, or is it a faulty ground within the circuit??

Any advice would be much appreciated!

john kaminski 11-16-2012 01:07 PM

Are the wire connections reversed ??

jccny13 11-16-2012 01:14 PM

Thanks for the reply.
Are you speaking about the electrical harness that clips onto the actual coolant sensor or where the wires meet the coolant gauge in the back of the instrument panel?
I am going to try switching the harness on the sensor as we speak

jccny13 11-16-2012 01:53 PM

Negative on switching the harness. It only goes on the sensor one way.
After i took the harness off and put it back on, the gauge started out on dead center and took about 60 seconds this time to hit the light on for over heating.
My car has been sitting for about 6 hours as well, so coolant should not be anywhere near hot.

jccny13 11-16-2012 03:10 PM

I would also like to note that my heat does not have much heat to it. It does come out warm, but not hot.
I have checked all the obvious items with this....plan on changing cabin filter in the am to see how dirty it is....
any chance this has to do with my issue with temp gauge??

ZeGerman 11-16-2012 03:46 PM

If the dial below the center vent is turned to the red and you still are unable to get serious heat, you have air in your cooling system.

jccny13 11-16-2012 03:49 PM

Yes it is, been looking at the other posts and def. checked that.
I guess the coolant system needs to be bled at his point?
The bleeder on the radiator should do the trick??


ZeGerman 11-16-2012 03:55 PM

Yes, I would certainly do that. You can use the instructions at the bottom of this DIY:

It also helps to get the front of the car higher than the rear, either by jacking it up or parking on an incline (it allows trapped air to rise to the top more quickly).

john kaminski 11-16-2012 04:51 PM

Air in the system isn't the only thing that causes low heat. A broken thermostat that is stuck in the open position will cut the heat considerably - I had this problem which made riding with the top down on cool nights not fun ! If nothing has been done with the cooling system that would introduce air, most likely its the thermostat.

Ok so the temp sensor wires can't be crossed - just a wild idea but at times our fuel gauges will stop working for no good reason and you just disconnect the battery for a few hours and presto the fuel gauge works. Maybe the temp gauge is the same ???

All times are GMT -7. The time now is 12:13 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
© 2001- VerticalScope Inc. All rights reserved.