I was always told to check the oil when it is warm (after the car has been running, but cooled off enough to touch things). However, reading through some of these posts, people are saying to check it when it is cold.

Which is it, or does it matter?

 

I personally find that with my engine I get accurate readings with the car warm. Ie, I'll drive it for 10-15 min, let is sit for 5-10 min and then check. If I check in the morning I get a low reading.

 

The owners manual says to check it when it's warm.