Oil and radiator control = optimal engine performance?

[gpang788]

Hi all, have been playing this sim for a while but have just recently come to realise after reading other threads that oil and radiator settings seem to affect plane performance i.e. climbouts, speed at various alts?

Pardon my ignorance but can someone explain to me how this happens?

In the 109 for instance, I normally fly it with oil and radiator fully opened no matter what happens.

Is this advisable?