You check the automatic drain valve on an air tank and find it caked with dirt and not draining. What should this tell you?

Pick an answer

1. The tank is simply too full of air to drain
2. The dirt indicates a fuel leak rather than an air system issue, since both fluids can leave a similar-looking residue around a fitting
3. A clogged drain valve is a cosmetic issue with no effect on moisture buildup
4. The valve may not be removing moisture and oil as intended, and the tank should be checked and drained manually

Correct!

Not quite. The correct answer is highlighted.