I have a 97 850 with a slow leaking evaporator. Rather than paying $1500 to get it replaced, I've opted to recharge the A/C every few years whenever the system begins to cycle warm/cold during the summer.

Today, rather than paying someone to do it at the local Jiffy Lube or Valvoline, I opted to use the "EZ Chill Quick Charge System" from Interdynamics ($29.95 from Autobarn.com). The kit comes with a re-usable pressure gauge shaped like a gun and a 14oz can of R-134a pre-mixed with oil and leak sealer built to plug into the gauge.

With the car on and the A/C set at full blast for five minutes - both dials set in the blue zone and the fan set at max -- I popped the hood. I then unscrewed the dust cover over the low pressure port, which is located behind the headlight on the passenger side [the thing marked 6nm max], attached the gauge to determine the baseline pressure, and then refilled the system until the system reached 40 psi on the gauge. Took a grand total of 2 minutes. The instructions were understandable and easy to read.

I don't own stock in Interdynamics or Autobarn, but this was the easiest A/C charge to date. Hopefully this should help those 850 owners out there that are still trying to figure out how those R134a kits sold at Walmart work or how many cans to add without overloading (and therefore damaging) the system.