Possible Duplicate:
Is running the engine for five minutes before driving beneficial for the car?

My wife, her dad, and my dad says so.

They said that before you drive a car, you need to turn on the car for a few minutes, let the engine heat up, then drive.

My dad has a different theory. You don't need to heat up the engine, however, the engine oil is more well distributed when the car is running for a few minutes with no load.

Which one is right?

How it really works anyway?

Is it even true?