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Re: '85 318i Temperature Gauge Sending Unit Calibration

RBeard3447@domain.elided wrote:

> Does anyone know of a calibration (verification) procedure for the
> temperature sending unit?  My gauge appears to function normally until a
> > little past the halfway mark.  After that, in the span of 10 seconds, it can
> be at the 3/4 mark.  It never goes any further.  This can occur during
> driving at a steady 75mph.  Then wham!, you can look down and the gauge will
> be back at the 1/2 mark.  The gauge doesn't appear to be stuck (thumping it
> doesn't work).

> The same thing seems to apply if you stop, turn off the engine, let it sit
> for 10 minutes, then start it again.  The guage will always be at the 3/4
> mark.  That's not unusual, but what is is that the guage will linger at the
> 3/4 mark for about 30 seconds, drop to midway between 1/2 and 3/4, then wham!
> drops immediately to 1/2.

Have you checked the thermostat? The description sounds an awful lot like the
thermostat is opening at a higher than normal temp, but closing at the right
temp. Removing it and testing in a pan of water should verify this.

Hope this helps.

Evan
'87 325