Trying to work out if the exhaust was a bit more smokey than it should be for the milage, the car dealer held his hand over the exhaust pipe outlet and then smelt his hand and invited us to smell it. He said if its burning oil you can smell it on the hand.
I've never heard of that one before. I know my sense of smell is not great, so could not tell if this was a valid method or not, even if i smelt it. Would you think this is a valid method?