My ac compressor on my 95 audi 90 turns on and off continually, and does not blow cold. does it just need a recharge, or could it be more?

There is only a high side R134 connector on the audi 90 1995 located on the front radiator. There are two problems that can cause clutch cycle on this car. The low pressure switch could open below 153-217 PSI to stop the evap from freezing indicating you have a low charge. The meter restrictor could be clogged with compressor bits and pag/water goo. Pag oil and water in the system forms a black goo clogging the restrictor causing the high pressure switch (red) to open at 408-450 PSI interrupting the clutch circuit. You could just try to add 4 oz of R-134 at a time to the system to see if the situation improves. The trick is to do this in the morning while the system has rested overnight and the engine is very cool. Hold a refill can upside down so you deliver liquid freon through the high pressure fill. You need to use a vacuum pump to remove the air from the line or break federal law and vent freon into the host to flush all air from the host. Then draw exactly 4oz of freon. You must use a scale for this. Borrow one from your local drug dealer. If the metal tube from the firewall to the small tank behind the right head lamp flash cool you are very near having a good charge. You want to charge the system in 4 oz increments until the system will not cycle when the system is blowing hot air and the engine is hot. The system is supposed to turn off the compressor clutch when the evap is blowing 43F air through the air vent between the passengers with the side vents closed and rec turned on at 2000 RPM with a water hose on the condensor. You should buy a good AC pressure set with a R134 top of can tap for R134. This system takes 650gms of freon from empty. You should really buy a pressure set and vac pump and a recovery compressor and tank to work on this system. But, you can do almost everything you need with a pressure gauge and can of freon. If you ever open the system replace the accumulator with a Visteon 500003 and a 450040 orifice tube for about $40 from NAPA saving about $380 for the Audi label. The compressor can be had for $350 from any e-wholesale for a new unit. Always buy new because it is worth the $50 difference in cost because the new ones are quite. This is a simple but very good system. I like the pumps GM uses better, I wish Audi would use them, but 90% of virgin system issues are simply a low charge.

How may miles is on the car?

Get an AC LOW SIDE psi garage and check on the LOW SIDE hose PSI.


MAKE SURE IT"S LOW SIDE.

High side can shoot up to 140 +++ PSI

BE CARE REAL CAREFUL



If it has 45+ PSI then do a charge with the auto part store R-134A kit.


If it's below 45 psi then you has a slow leak. Fill up will be last only hours or weeks.


Fix it right and be good to our environment.