I have a confession to make. Last summer, one weekend, I was checking the oil level on the dipstick. Thought it was a bit low, so I opened the oil oil cap, placed it on the engine cover and added about 1/2 qt of oil. Then one thing lead to another, got called away to do something else and closed the hood. Two days later I open the hood for something quite unrelated and I realized that the oil cap is still sitting on the engine cover and obviously I had forgotten to replace it back. So I guess I must have driven about 60 miles with the engine oil cap opening open to the air! The van ran well during the time and six months later, it is still running fine. I didn't see any debris deep in the opening and with regular city driving it is not a dusty driving environment. I don't detect any change in engine sound and a oil change done two months later last fall was uneventful too. So now, I am allowing myself think about what could have happened during the time the cap was off and if I should do anything different and watch out for anything, after this silly oversight. Any thoughts, suggestions, advice is most appreciated. Thanks. BTW: Van is a 2002 Honda Odyssey with 207,000 miles on it.