water temp gauge

[dshiznitbmwe30]

I am installig an after market water temp gauge and I am unsure where the best place is to put the sensor. I have a 87 325is. There is a sending unit above the electrical fan switch that doesn't have anything hooked to it could I use that sending unit or where would you recommend I run it.

[jlevie]

The best place for the sensor is in the thermostat housing. You could eliminate the OE gauge sensor or replace the housing. The replacement housing has (for this engine) two extra threaded holes. One of which can be used for the sensor.

[dshiznitbmwe30]

Which sensor is the one, kind of a noob when it comes to the m20 motors. Cause it looks like there is two one is closer to the front on the motor and there is another behind it. I know my way around my m52 in my e36, just learning on my m20

[jlevie]

Normally the upper sensor is for the gauge. A simple way to check is to get the engine to operating temperature and pull the connector. If the gauge goes to cold that is the gauge sensor.

[dshiznitbmwe30]

That side of my vdo gauges don't work that is why I am instaling an after market gauge

[dshiznitbmwe30]

If I remove the factory water temp sensor will it affect the how the car runs at all? It may be a dumb question but I am unsure

[jlevie]

If I remove the factory water temp sensor will it affect the how the car runs at all? It may be a dumb question but I am unsure

Nope.

A non working temp gauge, more often than not, will be a bad connection where the gauge bolts to the PCB in the cluster or a bad SI board. Both of which are easier fixes than installing a separate gauge.

[dshiznitbmwe30]

So if I take apart the cluster it should be an easy fix? I have removed the cluster and looked at all the connections and they all looked fine. My tach and my MPG don't work on the cluster as well

[dshiznitbmwe30]

Which one of the two plugs can I remove the one with the brown or white connector?

[antil33t]

pull them both out, the one you can remove only has one pin. the temp switch has two pins.

[dshiznitbmwe30]

OK cool thanks

[jlevie]

So if I take apart the cluster it should be an easy fix? I have removed the cluster and looked at all the connections and they all looked fine. My tach and my MPG don't work on the cluster as well

Failure of the tach, econometer, and temp gauge is almost always caused by a failed SI board. It could be that the SI board batteries are just bad, but if they have leaked and there is any corrosion on the SI board it will have to be replaced.