Sauna on wheels! Can I recharge my 97 stang with 134a?

[Philossifer]

Originally Posted by Dr. B

Does anyone know what type of refrigerant is in 1997 Mustang (3.8L)? To my knowledge this is the 1st time it needs to be recharged. I bought a do it yourself kit at walmart but didn't want to screw anything up. Any advice is much appreciated!

Your A/C system uses R-134a.

If it needs refrigerant, you have a leak! My suggestion would be to undo all the fittings, clean them with refrigerant oil, replace any damaged o-rings if necessary and re-connect the fittings using a product called "Nylog."
Those pesky o-ring connectors will never leak again. (((AND I MEAN NEVER)))

Before you recharge add two ounces of "Ester" refrigerant oil into the accumulator (or any hose that can be easily accessed) then pull the system into deep vacuum for at least a half-an-hour. When you recharge, do it slowly until you get the coldest temperature out of the vent without having the High side pressure exceed 2.5 times the ambient outdoor temperature. While charging you should have the engine idle at about 1200rpms, the windows down, with the air on MAX A/C and the fan on high.

So if it's 90 degrees out, you (DO NOT) want the high side pressure to exceed 225 psig on the red gauge.
Example: (2.5 x 90 = 225 )
As you're charging, you might have to spray some water on the condenser if the high-side pressure goes too high. Spray water on it, let it equalize and continue to charge.

Then, when you've got the charge correct, roll up the windows and turn the fan on low. Watch the blue (Low side) gauge. When the pressure drops to about 19 psig, the compressor should cycle off. If it cycles off at a higher pressure than 19 psig, the system will not cool down enough and if it cycles off at a lower pressure than 19 psig, your evaporator will ice up. To adjust this, there is a cycle switch on the accumulator. (Black or silver can on the firewall) Unplug the harness from the cycle switch and inside the connector (on the switch) there is a recessed screw. Turn the screw counter clockwise (outward) to lower the pressure set-point of the cycle switch or turn it clockwise (inward) to raise the pressure set point of the cycle switch. Remember, you’re looking for the compressor to cycle off at about 19 psig on the blue low side pressure gauge!

If you want Ice Cold A/C that will last for a long time and you don’t want to do permanent damage to your system; It needs to be done right. So many people just suck in a few cans of refrigerant without repairing leaks, adding oil, monitoring pressures or pulling a vacuum......and the A/C might work fine for a while……..but over the long haul, it can and will cause much damage! Personally, I'd take the Wal Mart kit back. In the trade, A/C techs call these "Death Kits"
Good luck,
Phil