FAA Powerplant Written Practice Test

An oil tank with a capacity of 5 gallons needs what amount of expansion space?

1. 1 quart

2. 2 quarts

3. 3 quarts

4. 4 quarts

The correct answer is: 2 quarts

To determine the appropriate amount of expansion space needed for an oil tank, it is essential to consider the thermal expansion properties of oil as well as the capacity of the tank. For every gallon of oil, a rule of thumb indicates that an expansion space of approximately 1 quart is usually required. In the case of a tank with a total capacity of 5 gallons, the expansion would thus necessitate the calculation of roughly 5 quarts of oil. However, tanks are designed with a specific allowance for expansion to prevent spillage or overfill due to variations in temperature. Since the correct answer indicates 2 quarts, this means that while the total expansion is considered, it is not intended to fully utilize the potential expansion; rather, it establishes a balance that slightly exceeds the calculated needs while still containing the oil safely within the tank’s limits. This approach safeguards against overexpansion while allowing for adequate thermal expansion.