ASE G1 Auto Maintenance and Light RepairHeating and Air Conditioning (HVAC)Easy
A technician is performing a visual inspection of a vehicle's HVAC system. Which of the following would MOST likely indicate a refrigerant leak?
- AA loud clicking noise when the compressor engages.
- BA strong, moldy odor from the vents.
- CExcessive condensation on the outside of the evaporator housing.
- DOily residue around a connection or component.
Show answer & explanationAnswer & explanation
Correct answer: D. Oily residue around a connection or component.
Refrigerant, especially when mixed with compressor oil, will leave an oily residue at the leak point. This is a primary visual indicator of a refrigerant leak.
Why the other options are wrong
- A. A loud clicking noise from the compressor engaging could indicate a failing clutch or a low refrigerant charge, but it's an auditory, not a visual, sign of a leak.
- B. A moldy odor typically indicates microbial growth in the evaporator or ducting, not a refrigerant leak.
- C. Condensation on the evaporator housing is normal operation when the AC is running, not an indicator of a leak.
Refrigerant Leak Indication
Visual signs of refrigerant leaks often include oily residue due to compressor oil escaping with refrigerant.
- Refrigerant is often mixed with compressor oil.
- Oil escapes with refrigerant at the leak point.
- Oily residue is a common visual indicator.
Memory trick: Look for the slick spot, that's where the cold air slips.