I noted in a motocycle manual that measuring the oil level should be done "without screwing in the dipstick". It made me wonder about all the Lycoming O-320's, O-360's and my current IO-360 that have screw-in dipsticks. I've not seen any direction in any owners' manual, but it seems to me that there is about a 1/2-in difference in the readings between screwed in not. Anyone know what the correct procedure is? and does anyone have a printed reference?
dancfi