All Griffiths/Kuehl barrier hoses are configured to OEM specifications, meaning they bolt right on. If your 924, 944, 951, or 968 has non-factory hoses we can custom manufacture new barrier hose assemblies for you.
The average Porsche water-cooled 924, 944, 951, and 968 is over 30 years old. The original factory air conditioning hoses were designed with older technology. R12 refrigerant was inexpensive and its effect on the ozone level was unknown. This old-fashioned air conditioning hose line slowly leaks (permeates) refrigerant through its skin overtime.
It was common to “top off” or recharge the system on a yearly basis. Today, with the high cost of R12 it’s not wise to have leaks of any kind. With the introduction of R134a refrigerant the a/c industry determined that the original type hose leaked R134a at a greater rate than R12. To solve the problem a new type of hose was designed that has inner liner which reduces rate of permeation (leakage) of refrigerants through the hose wall. It’s called “barrier” hose. You should inspect your hose lines on a yearly basis, looking for cracks, signs of oil or dirt accumulation on the hose or near the hose fittings.
You may notice small pin size holes that are evenly spaced in a line running the length of your hoses. These are “pressure relief” holes which are installed by most hose manufacturers. The small holes allow pressure to escape in the event that the primary inner wall of the hose should fail under extreme pressure. The designers contemplated that it would be better to avoid a sudden eruption in the outer wall that could harm the vehicle or a technician working on the car. Under normal peak operating pressures refrigerant does NOT leak through these holes.
Your stock hoses are leaking refrigerant constantly because they are non-barrier hoses.
Kuehl brand Porsche 911 barrier hoses by Griffiths provide 5 layers of protection to minimize refrigerant leakage.