Okay I'm an AC freshman so I know nothing. My Compressor does not turn on when I turn the switch to AC or Max AC. What do I need (and how) to check?

 

After reading the FAQ and the directions that came with the recharge kit I decided to check the pressure in my system. with the van running and the A/C on MAX the gauge read about 10-15 psi. I went ahead and recahrged the system. When the system pressure got up to about 45 psi the compressor kicked on. I was on for less than a second (maybe one or two revs). As soon as it kicked on the pressure droped to 25 psi and the compressor turned off. When the pressure built back to 45 it cycled and shut off again. This cycling on and off contunued each cycle lasting longer than the last. The lable on my van says it holds 2 lbs 9 oz. I put two 14 oz cans in with stop leak and dye. The compressor runs for quite a while now and shuts down for gust a second then kicks back on. The gauge reads between 45 and 25 psi. I checked for leaks with a uv light and could not find any. The air comming from the vents is ice cold. I'm thinking that I need just a little more coolant to ge the pressure up high enough to keep the compressor on.

 

Actually John,
You've just done yourself a disservice by using that can of crap. It's not your fault, because the shady manufacturer makes things look and seem so easy. ("Just add our product and everything will be fine"). That is rarely the case. They use some slick marketing for their "snake oil" products. Way more systems are damaged by those products than are ever "fixed".

Here's your situation right now:
-The 10-15 psi (static) that you were reading was residual pressure in the system due to air being drawn in through a leak and pressurizing as it warms up. A small amount of refrigerant boosted the pressure. Air is a very BAD thing in an AC system. It drives up the high side pressure and can damage the compressor.
-AC sealers do not work and contaminate/dilute the oil in the system. This often leads to compressor failure.
-Due to the leak, and age in general, the desiccant in your accumulator is saturated with moisture. (and now sealer). It's basically dead and at risk for the desiccant bag rupturing and destroying the compressor. Moisture in the system quickly causes corrosion of the raw aluminum parts inside..

From here, you can either:
-Add a bit more refrigerant, cross your fingers and hope the high side pressure isn't up in the stratosphere. (Funny how Interdynamics never mentions the high side pressure on those nifty cans.). Be prepared to replace the compressor, condenser and other components if the compressor grenades. You might get lucky. For every "lucky" system, I see about 6-8 "unlucky" systems.

-Or you can back up and do the repair correctly and have a working AC system for a long time to come. To do that you will need to:
-Source a manifold gauge set and vacuum pump (and a can tap). You can often rent them from places like Auto Zone.
-Disassemble and solvent flush the system
-Oil flush the compressor.
-Replace all of the o-rings in the hose connections.
-Replace the accumulator and orifice tube.
-Add the correct amount of oil to the system
-Evacuate and recharge the system by refrigerant weight.
This is not "hard" to do if you have access to the right tools. It is time consuming, though.

At bare minimum:
-Have the refrigerant recovered.
-Evacuate the system down to 30" vacuum for 30-60 minutes.
-Recharge the proper amount of virgin refrigerant by weight.
You will still be taking a gamble, but you will remove the air and at least some moisture. It will improve the chances of saving the compressor greatly.

 

[quote=lsrx101;7619925]

-Disassemble and solvent flush the system


This is not "hard" to do if you have access to the right tools. It is time consuming, though.

quote]

Disassemble and flush? Do you mean take all the A/C components off the vehicle and wash in a solvent bath or is there a way to flush the system like one would with a radiator and then remove the hoses and replace the O rings?

 

[quote=sailorjohn;7620166]Remove all of the lines, condenser, accumulator and orifice tube. Flush each line, condenser and evaporator individually. Use a fully evaporating solvent like lacquer thinner or denatured alcohol, add about 8-10 oz to the heat exchangers and blast dry with lots of compressed air. Use an ounce or 3 for each line. The evaporator can be flushed in place, for obvious reasons.
There is AC specific solvent available (Dura-141) but it can get pricy. You'll need about a quart.
For the compressor you need to remove and drain it while turning the clutch. Add 4oz of refrigerant, turn the shaft and drain again. Repeat, draining the compressor as thoroughly as possible.

Sorry, there is no good DIY way to "closed loop" flush an AC system like you would a cooling system.
For a ton of good DIY info, check out the FAQ section at Automotive AC Information Forum - ACKITS.COM There's a section there just on flushing. Check out the main forum, too.

 

ahhhh yes, the one thing i usually leave to a pro.....Firestone shops work for me!

 

You and a lot of otherwise competent DIYers too.
AC work isn't tough once you are familiar, but can be daunting to some folks.