drill holes in t-stat?

Drilling a hole in the t'stat ( about 2.5mm diameter ), is for stopping heat shock at the radiator......also helps with bleeding air out of the system.
A fan shroud makes the engine fan more effiecent.....placement of fan depth in the shroud is also a key.....needs to be half way in/out...centre line of fan blades....makes the fan way more effiecent.
Running the correct mix of anti-freeze/anti-boil can raise the boiling point by 9*C.
An alloy radiator is far more effiecent than a brass/copper one too.