AC Recharge

I have a 99' Blazer that is in need of an AC Recharge. Can I do this myself and if so what do i need. Parts, Tools etc.?

All you need is a level head, safety goggles, A/C recharging hose and the refrigerant. All can be gotten for a flat $20 to $25 depending on how low your A/C charge is, and whether or not it is leaking to the point where it bled out all of it's PAG oil. Inspect your A/C system's tubing and hoses to make sure that they are secure and not leaking like a seive. Leaks big enough to leave oil behind that collects dirt will need to see professional servicing before recharging, IMO.

If you are good to go with no major leaks, then the question arises:

Are you just needing to top off a semi-cold, still running A/C system, or is it so completely depleted that the compressor kicks on and off quickly, or not at all? If merely low and not performing, a single can of R-134a can be had for $5, a tap hose and valve kit for another $15. If the A/C is completely inoperative, buy at least 2 cans.

If inoperative:

Locate the "LOW pressure" side of your A/C system. THe tap valve cannot fit the connector on the "High side" anyway - but on my truck, it's on the side of the accumulator...that's the silvery can-looking thing on the passenger side right behind the overflow tank for the radiator. There will be a black cap roughly 2x the size of a valve stem cap there. Remove it and make sure that the valve is clean. Screw the tap hose and valve assembly on the recharging kit onto the bottle of refrigerant. Make sure that the valve handle is turned all the way out so it's sharp needle does not pierce the can just yet. With that set, screw or quick connect your other end to the accumulator's valve. It will hiss and leak a little when you do this, but no worries. Now screw the tap valve on the can all the way in as if you were "closing it". This will pierce the can and allow the recharge to happen once you again back the tap valve back out all the way to its fully open position. Keeping the can upright at all times, find a safe place to leave it under the hood overnight. Seriously. The slow evaporation of the refrigerant in the can will force itself into the system just enough to at least get it running again so you may fully recharge with the second can as follows:

If it is operative and just cycling on and off quickly or just underperforming:

Leave the engine idling. Turn on your A/C to max/recirc. Roll all windows down, crank your fan up to max speed. Proceed as above in locating your accumulator's low pressure port, cleaning it and attaching the tap hose - mounting the can on the other side at the tap valve, connecting to the accumulator and then tapping the can to recharge. Again, keep the bottle upright so only gas flows into the A/C system. Getting impatient and inverting the can will ruin your A/C system as you will be injecting liquid into the side of the system that is more accustomed to injesting recirculating oil and decompressed gasses. But at any rate, keep adding the refrigerant until the A/C compressor stays engaged at maximum output, and your inside vents output chilled air that is roughly 30~40 degrees cooler than ambient air temperature outside the truck. The use of a small food prep thermometor works well here, and can be picked up inexpensively at Walmart, or even at an Ace Hardware shop. Anyway, when done and pumping out enough cold air for your own personal arctic front, close the tap valve atop the refrigerant can, then release the tap hose from the low pressure port. Be sure to put your cap back on over the accumulator's port and that's it.

If your A/C system is leaking enough to see not oil, but just a bit of road grime, there are cans of "all in one" recharge that contains a phosphorescent dye (To visibly track severe leaks) refrigerant charge, PAG oil, PAG oil booster (To reduce friction) and a seal conditioner. Injecting this stuff as described above can get your A/C working in short order, but be careful to not overcharge. Put in just enough to get chilled air 30~40 degrees under ambient air temp and you will be good to go. Good luck, I hope this answers what you need to know. Oh, do not use the "All In One" stuff overnight to start a completely depleted A/C system. If your A/C's completely bled out, and there is a ton of light oil everywhere you look on top of there NOT being any gas leaking out when you connect the tap hose - you are going to have to take it to the shop.

A/C's that are totally bled out collect air and moisture. Your A/C will require a thorough, professional service to get it operating safely again. This will include taking it apart at the joints and compressor fittings to install new seals, hoses and possibly tubes too. Your condensor will need to be inspected for physical damage too if no hoses are suspect/leaking as well as your evaporator core. Then once assembled, solvent will have to be flushed through the entire system to remove all moisture and old oil. It is then evacuated to remove nearly most of the air in the system, then topped off with PAG oil and refrigerant charge. That requires specialized equipment that most of us armchair and weekend mechanics *wish* we had. Anywho, good luck and let us know how it goes. If you loose fingers or an eye doing it, post photographs! :D

1.) Go to parts store and buy a recharge bottle with the oil included in the mixture and a gauge on the hose.

2.) Turn on engine and turn AC to max.

3.) Hook hose of can to the low pressure connection on the accumulator.

4.) fill system until it is in the safe range.

Here is the product I recommend.

http://www.id-usa.com/how_to_recharging.asp

Blazer LT,
Is there a certain type freon or whatever it is now, I should get?

Can someone tell me what the pressure reading should be on a fully
charged a/c system? 95 Blazer LS 4x4 4.3W.
In the summer months, my a/c will quit working after about a half
hour of driving and I think it might be low on refrig.

Read my post above - "R-134a" That is the only refrigerant you will find for regular Joe consumer A/C systems in cars and trucks. ;)

Blazer LT,
Is there a certain type freon or whatever it is now, I should get?

Your A/C system is charged properly when you check the vent temperature and it is between 30~40 cooler than ambient air. So, if it is 75 degrees out that day, your A/C when charged will blow air that will read 35~45 degrees at the vent. Use a refrigerator or food prep thermometer inserted into the vent to check.

Can someone tell me what the pressure reading should be on a fully
charged a/c system? 95 Blazer LS 4x4 4.3W.
In the summer months, my a/c will quit working after about a half
hour of driving and I think it might be low on refrig.

Blazer LT,
Is there a certain type freon or whatever it is now, I should get?

Yes, go to Autozone and get the recharge kit that has the R134A with the oil included in the charge. Make sure it is the measure and charge from Interdynamics.

Makes it SOOOO easy to recharge the system.