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Symptoms of a Bad or Failing AC Low Pressure Hose

Low Pressure hose

An AC system is made up of a variety of components that work together so that the AC can produce cold air for the cabin. The AC low pressure hose serves the function of carrying the refrigerant that has passed through the system back into the compressor so that it can continue to be pumped through the system, providing cold air. The low pressure hose is usually made up of both rubber and metal, and has threaded compression fittings that secure it with the rest of the system.

Because the hose is subject to constant pressure and heat from the engine bay while in use, just as with any other component on a vehicle, it will wear over time and will eventually need to be replaced. Because the AC system is a sealed system, then there is a problem with the low pressure hose, the entire system can be negatively affected. When the low pressure AC has begun to fail, it will usually display a few symptoms that can alert the driver that there is a problem.

1. Crimps or kinks in the hose

If the low side hose receives any physical damage that kinks or bends the hose in a manner that obstructs the flow, it can cause all sorts of problems with the rest of the system. As the low side hose is basically the feed hose to the compressor and to the rest of the system, any kinks or bends that prevent refrigerant from flowing into the compressor will negatively affect the rest of the system. In more serious cases, where the flow has become obstructed enough, the AC will be unable to produce cold air. Usually, any kinks or crimps in the hose will happen as a result of physical contact with moving parts or from heat exposure from the engine.

2. Traces of refrigerant on the hose

Because AC system is a sealed system, any traces of refrigerant on the hose can be an indicator that it could possibly be leaking. The refrigerant that passes through the low side hose is in gas form, therefore sometimes leaks will not be so obvious as they are with the high pressure side. Low side leaks will present themselves as a greasy film somewhere on the low side hose, often on the fittings. If the system is continuously run with a leak in the low side hose, it will eventually empty the system of refrigerant, and the vehicle will be unable to produce cold air.

3. Lack of cool air

Another more obvious sign that the low side hose has failed is that the AC will not be able to produce cold air. The low side hose carries refrigerant to the compressor, so if there is any problem with the hose, it can quickly transfer to the rest of the system. Usually the AC system will start having problems with producing cold air once the hose has completely failed.

Because the AC system is a sealed system, any sort of problems or leaks with the low side hose will negatively affect the rest of the system. If you suspect that your vehicle’s low side AC hose, or any another AC component, have the AC system inspected by a professional technician, such as one from YourMechanic. If necessary, they will be able to replace your AC low pressure hose for you.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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