A/C issue

Hello All,
 
I recently returned from a road trip from Charlotte, NC to Washington, D.C.  On the way to D.C., my A/C worked fine, blowing cold air, etc.  Three days later, on the return trip, it was not blowing cold air.  I pulled over and noticed that the compressor would engage and then disengage about every 5 seconds or so.  Any ideas as to what may be causing this?  As a side note, I had to replace the radiator the night before we left because it had a crack in the plastic tank.  Thanks in advance!
 

Sounds like a low charge. You might want to try a recharge kit from your favorite autoparts store.

Yah that does sound like low charge, could be high charge but you havent added any in that time so very unlikely. You will probably want to get some leak detector when you add some r134a so you can see if you have a leak.

You know, my AC hasn''t worked for the past two summers.  It''s been low on my priority list of things to take care of, but how easy is it?  I know nothing about AC fixes.  How do you recharge it?  Is it dangerous for someone with little or no experience in AC work?

Well refilling is simple you can just buy the cans with the house and gauge and connect it to the low port on the accumulator.

You mind giving us a little more detail?  Does it come with instructions?  Are there any precautions you need to take before doing it?

Yah they have full instructions on the package and refridge can. As for precautions they are also on the packaging and can, basically dont breath the stuff in dont spray in air and such.

You will want to get the compressor running first.  Sometimes you can simply fill the system and the compressor will start once the pressure rises, but it I have had more than one not start the compressor this way (even with a LARGE bottle attached).  You can basically remove the A/C relay and jumper pin 30 to pin 87 to engage the clutch.

If the system has not been charged you need to pull a vacuum first.  This will remove all the moisture from the system.  You will not get the same performance if you do not pull a vacuum from an empty system.   

My repair manual also says you can jump the two pins in the low pressure sensor wire going to the accumulator to kick the compressor in.