High Ambient Temperature

[Greig Smith]

Thrmostats should have soem sort of bypass even if just a generous hole. Otherwise can get very odd effects.

!00% agree with Bob, I had a thermostat fail once, cost me a cylinder head gasker on a 1300 twin cam Alfa. Since then I've drilled 4 or 5 holes in every one I fit. - 1/4" or 5mm holes are fine, no science here, just drill holes around the perimeter half way between the middle & the edge. Car takes a bit longer to warm up & once the thermostat opens it's academic anyway. Nowadays I run my cars on Evans Waterless Coolant which is like molasses when cold, so at least there's some movement of the stuff through the thermostat when cold, once at operating temps it's like water

Aye
Greig