My a/c is not cooling enough. I do not find the valve to conect the hose to recharge with freon. Any ideas?

 

AC not cooling well is not as easy as just adding more r-134a to the system, besides on these cars luckily audi was smart and only put a high side service valve on the car to prevent tards from servicing there own AC and working on it, but let me give you some helpful professional advice to check out your ac system and give it a good check. first what you need to do is get what are called air conditioning manifold gauges, this set of gauges will have a yellow charge hose, a low side connection and a high side connection, although with your car you cannot charge through the high side using these gauges you need to have a $4000.00 machine to do that. but anyhow you will hook the high side gauge up to the high side service port located on the condensor in front of the radiator. make sure when you do this that both valves on the manifold gauges are closed, you will never need to open the valves on the manifold gauges to check your system. then its quite simple to check your charge, start your car turn on your AC and have a helper hold the car at 2000rpm for you. now you will notice the needle on the highside gauge will move, you will see it go up and stay there for a bit and then come back down and go back up, this is normal as long as it is not extremely rapid. now your charge should indicate this formula here ambient temputure*2.42= low high pressure threshold, ambient pressure*2.42+40=high high side pressure threshold, so basically say its 90 degrees outside your high side charge should be anywhere btwn 218 to 258 psi. Usually an inefficent AC system cooling is an overcharged situation, you actually want your AC system to have the lowest possible charge for it to operate correctly. but if its too low the AC compressor will not kick on long enough to provide cooling because the pressure will be so low that the temputures that would come out would be so cold it would freeze the evaporator and that is what the low side pressure switch is for, to prevent evaporator freeze up which will damage the AC system. if you see a rapid bouncing needle on the high side gauge during operation it will indicate bad reed valves inside the compressor, and if the high side pressure is just extremley high like 400 psi or so, start looking for severe frosting on the system as this will indicate a clog in the system.

 

Thanks,
I do have the manifold gauges and it is confirmed that it doesnt have enough freon. But the question is how to charge freon, is not a DIY thing, even though I have the manifold?
Tks

 

no, you can't recharge your system, you'll have to take it into a shop to have it done...don't let them charge you too much, the job is very simple, it just has to be done by a huge, incredibly expensive machine

 

gr8 tips TKS!!!

 

yea unfortunately only DIY can go through low side port as that is suction side of the system, high pressure side is the discharge side so it wont suck enter the system.audi didnt put a low side port on the system im guessing to keep people from servicing there own AC only a guess though, but i can tell you as a technician that alot of people screw there own AC system up and dump refrigreant in there with no idea as to what they are doing so imo its good that there is only a high side port for that, but a pain in the fact of qualified DIY'ers as you sound like yourself.

 

My AC is not blowing any cold air, just warm or hot air. There is a significant noise coming from the engine from the area of the belt and pulleys in front of the engine. What does this means?