RE: <E30> temperature gauge goes crazy, but the actual temp is no rmal

["Fadeev, Alex" <alex.fadeev@xxxxxxxxxxx>]

Mark Z. [mailto:zarich@domain.elided] wrote:
> 
> Good day, all; the car is an '87 325is. Anyone seen this? The 
> problem is intermittent. Usually, the temp gauge works fine. 
> But sometimes, the following will happen 1.) The gauge will 
> slowly sweep up into the red, lets say, within a minute or 
> less, from the 1/2 way mark. Then it will sweep back down 
> below half, when it feels like it. And, 2.)sometimes, it will
> jitter or bounce around, basically oscillate rapidly. It will
> bounce from full cold to full hot, even.
>
> A local independent BMW garage tested the actual temperature 
> of the engine with some kind of "scope" or external device, 
> and they said all was normal, so it seems the gauge is going 
> crazy, rather than the engine doing strange things like 
> heating and cooling in some funny way. They did remove the 
> gauge cluster and resolder the joints back there, but that 
> didn't help, as it happened again. What should we go after 
> now? Thanks in advance.

Mark,
Nothing to worry about. This is a very common E30 issue.
Your temp gauge is experiencing a bad ground connection. The ground is the
nut that holds the temp gauge to the instrument cluster. 
Take the cluster out (see Bentley for details minus the part about removing
the steering wheel). Tighten the nut, put the cluster back in. The temp
gauge will behave for another couple of years. Repeat when necessary.

good luck,
alex f

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