A dipstick is a long, thin metal rod that is used to measure the level of oil in the engine of a truck. The dipstick usually has markings on it that indicate the minimum and maximum levels of oil required for proper engine function. The dipstick is inserted into the engine through a designated hole and then withdrawn to check the level of oil. This part is an essential tool for maintaining proper engine health and preventing damage due to insufficient lubrication. It is important to regularly check and maintain proper oil levels using a dipstick like this one to ensure optimal truck performance.