CDL Air Brakes TestAir Brake System PartsHard
A driver is inspecting the air tanks on a commercial vehicle. When draining the tanks, they notice a significant amount of oily water being expelled from the drain valves. What does this most likely indicate?
- ANormal condensation build-up in the air tanks.
- BA leak in the air compressor's cooling system.
- CExcessive wear or damage to the air compressor.
- DA faulty air dryer that is not removing moisture.
Show answer & explanationAnswer & explanation
Correct answer: C. Excessive wear or damage to the air compressor.
While some condensation is normal, a significant amount of oily water indicates that the air compressor is passing oil into the air system. This is a sign of internal wear, such as worn piston rings or seals, which allows engine oil to contaminate the compressed air.
Why the other options are wrong
- A. Normal condensation is primarily water, not a significant amount of oily water.
- B. Air brake systems typically do not integrate with the engine's cooling system in a way that would introduce coolant into the air tanks.
- D. A faulty air dryer would result in excessive WATER, but not typically oily water unless the compressor is also failing.
Air Compressor Internal Wear
Degradation of internal components (e.g., piston rings, seals) within the air compressor, leading to oil contamination of the air system.
- Results in oily water in air tanks.
- Reduces compressor efficiency.
- Can contaminate and damage other air system components.
Memory trick: Water is normal, but oil is a compressor's 'soil'!