Automotive AC Hose Repairs

When you switch on the air-conditioning system and the compressor does not engage the most common reason is low Freon reserve. Problems with AC hoses or the O-ring sealing them to individual components are common reasons for refrigerant to escape. The routing and movement that naturally occur can cause worn spots on rubber hoses that will eventually leak.

Replacement parts are usually sourced from a manufacturer’s dealership or ordered after market. Although this can be the fastest and most expensive way to go, it may not be possible on 15 to 20-year-old automobiles. Part warehouses don’t usually stock replacements for really old cars. Here we will address a cost-effective alternative and provide a few facts on the operation and servicing of automotive AC hoses.

Types of Refrigerant Lines

The major components of an air conditioning system all have an inlet and outlet connection. It’s the refrigerant lines that connect these parts together allowing them to function as one. O-ring seals are provided at the various connections providing a tight seal while allowing for some flexibility to absorb vibration and movement. This design also facilitates the replacement of individual pieces.

All automotive AC will have at least three major refrigerant lines. These include the suction hose, liquid line and the discharge. The suction hoses are located between the outlet side of the AC evaporator and the inlet side of the compressor. It’s referred to as the suction side because this is where the compressor uses vacuum to pull in refrigerant. These are low pressure hoses that should be cool to the touch when operating and larger in diameter than the others found throughout the system.

High Pressure Tubing

The discharge line connects from the outlet of the compressor and runs to the inlet of the AC condenser located out in front of the radiator. This can cover a lot of ground on some automobiles and therefore is often the longest. The liquid line connects the condenser outlet to the receiver drier also known as the accumulator on some applications. This is the only line that is carrying Freon in the liquid state hence its nickname.

Discharge and liquid lines are always very warm to the touch and easily distinguishable from the much larger diameter suction line. Both of these high pressure hoses are made up mostly of aluminum tubing but can contain small sections of rubber hose to allow for flexibility and safe routing in the engine compartment. Any rubber hose utilized in an air conditioning system is specially manufactured to carry refrigerant. Vehicles that use the R134A type of Freon have an additional layer of rubber that serves as a barrier to prevent the refrigerant from escaping through the pores of the hose.

AC hose Common problems

When Freon leaks are detected from hoses, problems can often be further isolated to the O-ring connection. Telltale signs of a leaky connection is moist looking dirty spots. When refrigerant leaks out it leaves deposits of lubricating oil behind. Dirt from the engine compartment will stick to this wetness. These areas should be cleaned, disassembled and inspected after the remaining Freon is recovered. New O-rings can be obtained from any parts store. It is highly recommended to lubricate replacement O-rings with a liberal amount of clean refrigerant oil.

Although a large percentage of cars go to the junkyard with original equipment air-conditioning hoses installed, problems can still occur that require service. Rub through and worn spots on rubber sections are more common on older vehicles with high mileage. Slight movement over long periods of time can wear away the outer covering exposing the inner core. Freon is capable of permeating rubber and therefore can start escaping. Catastrophic failure can also occur during auto accidents tearing lines completely open.

AC Hose Repair Tips

When repairs are needed, shops will just include the replacement assembly in the estimate and not offer options to the consumer. It makes sense for them as it’s the fastest way to resolve problems, plus they make a profit marking up each individual part. Replacing with new is far from the only option available. Low mileage used parts can often be found in salvage yards. When these types of replacements are used they must be flushed thoroughly using standard procedures before installation.

The other option available is repairing the original equipment. There are companies that specialize in manufacturing hoses. One popular franchise found throughout the U.S. is Goodyear rubber products. This company manufactures specialized hoses for many different uses including farm machinery, heavy equipment and automobiles. This is the type of store that somebody would find a replacement hydraulic hose for a Caterpillar bulldozer. These locations provide walk-in or mail in services, ship worldwide and can manufacture by application.

All automotive air conditioning systems will have three major hoses. The suction, discharge and the liquid line. When refrigerant leaks are isolated to their connections there is no need to replace the hose. The remaining Freon can be recovered and just the O-ring replaced. On systems that are opened to the atmosphere for longer than 5 minutes consider replacing the accumulator. Hoses that carry refrigerant are manufactured with a barrier that prevents small molecule vapor from escaping. Replacement parts can be sourced new from dealerships or an aftermarket supplier. Damage refrigerant lines can also be repaired by companies that provide hydraulic hose service for heavy equipment and farm machinery.