Originally Posted by AF

There's always two sides of this arguement, whether you should measure cold or hot.

When the car is hot the oil is thinner, and there will be oil in the head versus cold where it is thicker and it's all sitting in the bottom of the crankcase. I really have no preference and just compensate in my head for any inaccurate readings.

The dipstick really is a terrible measurement for oil in the engine but until they come up with something better we're pretty much stuck with it.

As far as draining the oil, I'll usually just let it drain and go watch TV or eat lunch or something and come back.

You can pour 4.5 quarts in, let the car run for 10 seconds, then check the oil level again. If the engine is hot, that's probably as accurate of a reading as you'll get from a dipstick.