All Griffiths Kuehl barrier hoses are designed to match OEM, meaning they bolt right on. Hose lengths and fittings are identical to factory specs. If your 928 has non-factory hoses we can custom manufacture new barrier hose assemblies for you.
The average Porsche “shark” 928 is at least 30 years old. The original factory air conditioning hoses were designed with older technology. At the same time R12 refrigerant was inexpensive and it’s effect on the ozone layer was unknown. The old hoses leak or permeate, refrigerant through the rubber. It was common to recharge, or top off, the system on a yearly basis. Today R12 is very expensive and it’s not wise to have leaks of any kind. R134a refrigerant was introduced but actually leaked from the old hoses even faster than R12. To solve the problem, a new type of hose was designed to include an inner liner which reduces refrigerant leakage. This new type of hose is called Barrier Hose.
You should inspect your hoses every year. Look for cracks and signs of oil / 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.