HVAC & AC Lines

Air-conditioning lines carry refrigerant around the sealed loop between compressor, condenser, expansion valve and evaporator. The line kits here are made for engine swaps, where the new engine’s compressor sits in a different place from the original, so the factory hoses no longer reach.

The loop runs at two pressures. The compressor sends hot, high-pressure gas to the condenser, where it sheds heat and turns liquid.

After the expansion valve or orifice drops the pressure, the refrigerant boils in the evaporator and draws heat out of the cabin air. It then returns to the compressor through the suction line. Every joint must hold refrigerant and its oil for years without leaking.

Points to check:

• Listing: each kit is listed for one engine swap in one chassis, both named in the title, so match the engine family and the car.
• System parts: confirm the refrigerant type and charge on the label under the bonnet, and whether the condenser and evaporator are still the originals.

Before an AC system is opened, its refrigerant must be recovered with proper equipment, so leave that step to a qualified AC technician. Fit new O-rings, lubricated with the system’s own oil, and renew the receiver-drier or accumulator, as its desiccant saturates once the system has been open. The system is then evacuated to remove air and moisture, leak-tested and charged by weight. Route the lines clear of exhaust heat and moving parts, and clamp them so engine movement cannot chafe them.