Your car's air conditioning system relies on refrigerant to keep you cool and comfortable, even when the sun's rays are blasting into your cabin. The refrigerant needs to travel through the system as both a liquid and a vapor, and it relies on several hoses to move between the compressor, evaporator, and other components. A hose failure can result in lost refrigerant and a system that can't keep you cool.
Despite their appearance as seemingly simple components, air conditioning hoses can fail in various ways. Understanding these three potential failure modes for your hoses will help you recognize when your car's AC system may need attention.
1. Failing O-Rings
Your AC hoses connect to the pricier parts of your air conditioning system, such as the compressor. However, each connection is a potential failure point. Most hoses bolt into their connection points and use an o-ring to keep a tight seal. When installing a new hose, you typically grease these o-rings with AC oil to keep them supple and allow them to fit on more quickly and easily.
Unfortunately, these o-rings can dry out and harden over time. An o-ring that becomes hard and brittle will eventually crack, allowing your system to leak refrigerant and lose pressure. Since these o-rings are often part of the hose assembly, you'll usually need to replace the entire hose if it's leaking at either seal.
2. Cracking Rubber
AC hoses often need to be flexible to snake through the engine bay and reach around tight bends. Manufacturers typically use more durable hard lines where possible, but most automotive AC systems require at least one flexible rubber hose. As with the rubber o-rings or gaskets that seal hose connections, the outer lining on the hose can also become brittle and fail with age.
Although it's not easy to spot a refrigerant leak without using a special dye, a cracked or leaking hose may leave a noticeable layer of grease. Note that cracks won't always be visible with a quick inspection since they can be small, and bends in the hose can obscure the signs of cracking.
3. Internal Collapse
Refrigerant and AC oil will degrade the rubber on your air conditioning hoses, so manufacturers use an internal liner to protect the outer hose from damage. Unfortunately, these internal liners can sometimes fail, obstructing refrigerant flow. Unlike other hose failures, an internal collapse will not necessarily lead to a loss of coolant.
Buying high-quality replacement air conditioner hoses and relying on trained professionals for installation are the best ways to avoid these problems. If your AC system isn't keeping you cool, it's a good idea to schedule an appointment with an experienced AC shop to ensure your air conditioning hoses are in good working order.