: We've had a spell of triple digit temps here in the SF Bay Area and my '91 535 is doing something curious that bothers me.

: Running the a/c with a couple of passengers, stopped at a light in stop & go driving, it doesn't take long for the temp gauge to start creeping up. Normal position without a/c is straight up, rock steady in all kinds of temps and conditions.

: I chicken out as the needle approaches the next mark on the gauge and turn off the a/c and within a minute the needle is back to center.

: Car has new thermostat/water pump/hoses/coolant. Fan clutch is fine, system is bled of all air. Aux fan comes on as soon as a/c is turned on (which Bentley corroborates), presumably in low speed mode. The only thing I haven't determined is whether the aux fan switches to high speed at a higher temp. Haven't checked the fan switch or resistor.

: Any ideas? Is this normal behavior and will the temp stabilize at a higher setting? Bothersome.

: Appreciate your input. Thanks in advance,
: Adnan