Should I check my oil when the car is off or on?
Should I check my oil when the car is off or on? 1. Park your car on level ground to ensure you get an accurate reading. Turn off the engine and wait 10 to 15 minutes for it to cool down. Manufacturers used to recommend that you check your oil when the engine was cold, to give the oil a chance to settle in the oil pan. Does engine oil go bad if car not used? The answer is no. This is especially true if you changed the oil right before you stored the car. There is no expiry date...