Whether your car is new or used, one regular maintenance check-up no car owner should neglect is checking the oil. But when should you do it? When the engine is cold (before you first start it in the morning) or when it's warm (after you've driven it and it's cooled down a bit)?
The generally accepted answer is when the engine is cold. That way you have a clear indication of the oil level. The oil hasn't heated and moved up the dip stick and there's no oil coming down off the inside of the engine. There's also no need to wipe the dip stick and re-check after taking the initial reading. However, Ford Motor Company suggests that you check the oil when the engine is warm. This could be specific to their vehicles; perhaps their dip sticks are designed for a warm-engine reading. If you own a Ford, experiment by taking a reading once in the morning and once after driving. Compare the two readings and go with an average.
