Rapid Fluctuation of Temperature Gauge

Hi all. The temperature gauge (and maybe the actual temperature) on
my 2001 Z3 (3.0) has recently been acting up. It's fine while
crusing, but during idle (and specifically while on an incline) is
will rapidly go into the red (all the way to right so the light come
on), and then just as rapidly head back down to center. The is not
gradual...it's very fast both ways.

Any ideas?

Thanks.

more than likely the Fan Clutch. check the thermostat as well, but i would
BANK on it being the fan clutch.

--
Brent
"Brian" > wrote in message
om...
> Hi all. The temperature gauge (and maybe the actual temperature) on
> my 2001 Z3 (3.0) has recently been acting up. It's fine while
> crusing, but during idle (and specifically while on an incline) is
> will rapidly go into the red (all the way to right so the light come
> on), and then just as rapidly head back down to center. The is not
> gradual...it's very fast both ways.
>
> Any ideas?
>
> Thanks.

> Any ideas?

Have you bled all of the air out of the cooling system? My old E30/M20 used
to show bizarre temperature readings until I bled the system properly.

In my experience, when an engine genuinly overheats, it's a gradual (over a
few minutes) process. Rapid changes tend to be airlocks or electrical
problems.

Viscous coupling problems are not unknown, but it doesn't sound like it
from your description. Anyway, VC behaviour is easy to diagnose.

Al.