Engine cooling issues

[SparkyRnD]

if you use a threaded port in the engine, that is best and most accurate usually. If you don't have any available ports in the intake, and don't want to make a dual port, then go with a probe style switch inserted into the hottest part of the radiator (as close as possible to where the upper inlet hose is). That will give you almost the exact same reading as a port in the intake, within a degree or two usually, and will be good for activating the fan(s). Also, make sure to wire the fan(s) directly to the battery on a fused circuit, and have the controller with relay activate them. That way they are getting full power.