[2] How do I check that the viscous unit is slipping properly? Even in these chilly times the fan is hauling copious quantities of air in from startup.
TIA
Richard
[1] I have a spare pair of Kenlowe fans - complete with bracketry and thermoswitch etc. - previously fitted to my 3.5 RR Classic. Can I install it in my 3.9 Classic? Is it advisable? ISTR the 3.9 rad cools both water and oil (is that right) and wonder if the continuos cooling provided by the mechanical fan is safer than periodic fierce cooling from the electric fans.