Your vehicle’s air conditioning system is designed to keep you comfortable during hot weather, but when it starts to lose its cooling power, a refrigerant leak is often the reason. A/C leaks are not only inconvenient, but they can also lead to more serious issues if left untreated. Knowing the most common causes of A/C leaks will help you catch problems early and avoid more costly repairs.

If your car’s air conditioning isn’t working as well as it used to, here's what might be going on behind the scenes.

How the A/C System Works

The A/C system in your vehicle operates as a closed loop. It circulates refrigerant through the compressor, condenser, expansion valve, and evaporator to cool the air before it enters your cabin. When everything is sealed properly, refrigerant should stay inside the system for years.

But when leaks develop—often through worn seals, corrosion, or physical damage—the refrigerant escapes, leaving the system undercharged and unable to cool effectively.

Worn Seals and O-Rings

Over time, the rubber seals and O-rings that keep refrigerant contained can dry out and crack. Heat, pressure, and age take a toll on these components, especially around connection points such as the compressor and condenser fittings.

If these seals become brittle, they allow small amounts of refrigerant to escape. Because refrigerant is a gas at normal pressure, it doesn’t leave puddles like oil or coolant. Instead, the leak might go unnoticed until the A/C system loses its ability to cool.

Damaged or Corroded Condenser

The condenser sits at the front of the vehicle, just behind the grille, where it’s exposed to road debris, salt, and moisture. Rocks or gravel can chip the thin fins or cause small holes, while long-term exposure to salt can lead to corrosion.

When the condenser is damaged, it can develop pinhole leaks that are hard to detect without special tools. Even a minor leak here can reduce the system’s efficiency significantly over time.

Cracked Hoses or Connections

The flexible hoses that carry refrigerant throughout the A/C system are built to withstand pressure, but they can degrade due to engine heat, vibration, and wear. A cracked or worn-out hose may leak only under pressure when the A/C is running, which can make the issue difficult to detect without testing equipment.

Connections between hoses and metal lines can also become loose or corroded, contributing to slow leaks that affect performance gradually.

Faulty Schrader Valves

Schrader valves are used during A/C servicing to add or remove refrigerant. These valves have small internal seals that can fail, leading to slow leaks. If the valve core is defective or damaged during servicing, it can become a frequent source of refrigerant loss.

Technicians check these valves first during an A/C diagnostic, as they are quick to test and replace.

Leaking Evaporator Core

The evaporator is located inside the dashboard and is responsible for cooling the air before it enters the cabin. Due to its hidden location, a leak here can be difficult to detect and expensive to repair. Corrosion or manufacturing defects are common causes of evaporator leaks.

If your A/C loses effectiveness and the interior smells slightly sweet or chemical-like, the evaporator could be the culprit.

Preventing A/C Leaks

While some A/C leaks happen due to age and normal wear, regular inspections can help catch issues early. During an A/C service, technicians check system pressure, test for leaks with UV dye or electronic detectors, and inspect visible components for wear.

Keeping your cabin air filter clean, running the A/C periodically throughout the year, and parking in shaded or covered areas can also help prolong the life of the system.

A/C Inspections at Suwanee Service Station in Suwanee, GA

If your A/C isn’t cooling like it used to, or you suspect a leak, don’t wait for summer heat to make things worse. Our technicians can diagnose and repair refrigerant leaks before they lead to larger system failures.

Call Suwanee Service Station in Suwanee, GA, to schedule an A/C inspection and stay cool on every drive.