One of the seldom-weak points of the 4G63 is the rise in oil temperature. It is seen more often in circuit driving. The EVO uses a thermo switch that will work when the temperature gets around 85ーC (approx 185ーF). Yet when the oil temp is low, it will restrict the oil flow to the oil cooler constantly regardless of the temperature. Still it is easy to revert back to the OEM switch for winter use to prevent over cooling.
Features
Bypasses the oil thermo switch
Allows oil to flow into the oil cooler constantly regardless of the oil temperature
Can easily revert back into the thermo switch during the winter months to prevent overcooling
Benefits
Prevents the engine from overheating by activating radiator cooling fans