The Plus8 had Gems management.
It had a coolant temp switch in the top tank of the rad to trigger the fan. A proper screw in one not the older Otter version. There were options to get these with different temperature trigger points. Also aftermarket versions that could be adjusted to cater for winter v summer or track( high speed) v normal road use.
It had an old school mechanical thermostat. Possible to get variants for different temperatures. It also had small bypass holes in the thermostat plate to allow some flow through before it opened fully.
Standard fixed rad cap plus on the expansion tank a pressure release cap. I think a 15 psi one.
As the car didn't overheat my aim was to reduce the frequency of fan kicking in. The system was sentive to smallish variations in airflow through the rad. Slow traffic especially in summer. Hence improving that as the first route. Components had been checked and were ok.
