Personally, I don't like taking a reading when the engine's warm as you can pick up residue splashed oil returning to the sump which could provide a dangerously false reading.
On a cold engine (with ALL the oil in the sump) if you don't pickup any oil on the dipstick then you've got a big problem![Eek! :eek: :eek:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
On a cold engine (with ALL the oil in the sump) if you don't pickup any oil on the dipstick then you've got a big problem