E39 M5 Temperature

[quavey]

I'm sure its nothing to important but I have noticed of late the water temperature gauge in my E39 M5 doesnt sit totally central anymore. Its perhaps 1 or 2mm of dead center towards the cool side where as it used to be perfectly central once up to temperature.

It had a thermostat two years ago according to the service history, is it something I should do something about? Or just keep an eye on it to see if it gets any worse?

[E30M3SE]

The gauges are 'buffered', so a little movement is normal, but if you go into the hidden menu you can see what the actual temp is when fully warm.

[quavey]

Cheers mate I will give that a try. I didnt think it was to much to worry about.

[RichardM5]

Anything under 79C and the engine is running cool. It will then run rich to try and heat it up quicker which will cause loss of power and higher fuel consumption.

Failing thermostats are a common problem, best to use a genuine BMW part as they are guaranteed for 2 years, if they fail BMW will install the new part for free. Some thermostats fail after just a few months.

[shielsy]

unlock the test menu on the dash for the digital read out. test number 7 will give you the digital water temperature.

on mine 79 degrees is about 2-3mm from centre of the gauge.