trying to ad freon to ac unit. block in low side line under hood next to ac box has conection for gauge and another cap with a valve stem under it? does this shut the port off? if its a valve is it right or left hand thread? can't get it to move and port seems to be closed. please help thanks dave

Dave, to help you we need a little more information like the year and make of your vehicle.
This is important because the older vehicles used R-12 (which you can no longer buy without a license) and newer ones use R-134.

Most R-134 systems (including my MH),use a slip on connector. The gauge hose has a "push back" collar on it which allows it to pop onto the connection without loosing any of the charge the way that the threaded ones do. I also have a set of guages for my home A/C and they do have threads on them that work on the "lefty loosy, righty tighty" formula.

I started working on my own dash A/C when my dealer couldn't fix it after 3 tries. If you find yourself having to add more than part of a can of refrigerant, I'd recommend adding dye, too. I bought a leak detection kit (glasses, 12volt battery powered special light) and found a leak on a compressor fitting that my dealer's sniffer missed. For the extra $35, the leak kit was well worth it.

thanks so much for reply. i have 2004 gulfstream 8292 class A with workhorse W20 chassis. the push on fitting works fine but there is no path into the system. 2 black caps on the block. one is the service port and under other is this valve stem looking thing. is it a shut off valve? it must have some function. havn't tryed to turn it to the right for fear of breaking something. any ideas? thanks dave

Can't help much on this one, but am going to be very interested in the answers you get. I have tried it, the R-134 refrigerant went in, (a small) amount, clutch works ok, but no cool. The gage shows a full charge in the Green Zone.

Homer he also has a post down in the workhorse forum. AC revisited

Hi cannon man. Just make sure if you are adding freon to your air conditioning system not to hook the can up to the high side of the system. This could cause the can to blow up. Add freon through the LOW side. When the system is running this will be the cold side. Good Luck Gary.

If he's using the push on fittings, they're 2 different sizes, the inlet fitting won't fit the high side.

Just adding "Freon" to the system may not be the fix. If there is a leak, it needs to be fixed first which generally means removing the charge and evacuating the sytem to fix the leak.

Handling refrigerant can be dangerous for the untrained. Since you are not sure of the purpose of the block in question, you need t have a certified A/C tech look at your system.

37 years in the refrigeraiton business and I have seen what can be done to a system if you do not know what is going on.

Ken

ok tex, 37 years in biz. is that a valve in block or not? everything works. it makes cold air but warms up in hot weather. i'm just trying to check the preasure. thanks dave

I'm not familiar with the set up you have in your coach. I don't spend much time on A/C and auto A/C. When I need help, I go to someone that knows the equipmenet.

Ken