VW Passat (B5) A/C question

chapstic2001 · 06-01-2006, 12:31 PM

What is the capacity of the A/C refrigerant tank? I had my A/C unit replace 2-years ago (long story) and it was recharged at the same time. The problem is that now in the 90+ degree VA humid heat, I have noticed that it is blowing warm air. I refilled it with one 12oz can of Interdynamics R134A refrigerant, but it hardly seems to make a difference. I have been trying to get my hands on a gauge to tell me how full it is, but in the meantime I was hoping someone could tell me how my cans it typically take to fill one of these cars back up.

asphaltgambler · 06-01-2006, 12:57 PM

Most likely less than 2lbs total believe it or not. You need access to gauges to really tell what's happening.

BGCarrera32 · 06-01-2006, 01:26 PM

Usually you can buy a gauge and refill can combo in a box at Walmart. Most cars list the refridegerant capacity on a sticker underneath the hood.

Neilk · 06-01-2006, 02:07 PM

Just fixed an AC problem in my Jetta. It would blow hot air too.

Make sure the compressor is coming on when you switch the AC on. Also, verify that both (if a Passat has two) cooling fans are coming on as well. If one isn't working the AC goes into a sort of failsafe mode. Lastly, before you spend money at VW, get someone in your area with a VAG diagnostic tool to pull the codes off your ECU to see if anything is causing the AC to malfunction.

Very lastly.... near the front grill on my car, there is a sticker that indicates the AC recharge amount. See if you have that as well.

chapstic2001 · 06-01-2006, 02:14 PM

Thanks for the feed back and suggestions. I will take a peek at it this weekend.

BlueSideUp · 06-01-2006, 02:35 PM

The Passat has one engine driven fan and an electric fan. You can easily test the electric fan by turning the key to the Run position, pressing the A/C switch, turn the blower fan to 1. The electric fan (on the passenger side of the radiator) should come on.

Does the AC get colder if you are driving at highway speeds?

If you can get a gauge on the system you'll be able to see if the car has enough refridgerant. The low pressure switch is located on the passenger side of the condensor and can be reached without removing the front bumper.

chapstic2001 · 06-01-2006, 04:02 PM

I will be getting another can of refidgerant and a gauge this weekend and check out the fan. I think my dad has a VAG tool that I may be able to get my hands on and see what that tells me.

As far as it getting cooler at higher speeds, not really. It is still blowing "luke warm" as my wife likes to tell me.

BlueSideUp · 06-01-2006, 06:13 PM

Hmm if it doesn't change with speed the problem is probably not the fan. On a '99 the VAG tool will only tell you if there is a switch problem causing the compressor to not turn on. Unfortunately the compressor is located on the lower passenger side of the engine below the turbo. You still might be able to see it if you take off the plastic intake tube (two philips screws at the top of the grill). Check to see if the compressor is even turning on.

chapstic2001 · 06-05-2006, 08:59 AM

I put in another 10oz or so of refidgerant (22oz total), this time with a gauge. According to the gauge, it will only go to about 25-30 psi, right between the "needs to be filled" and "at fill level" readings. The full range tops out at 45-psi, but I cannot get it there. The fan comes on when I switch the AC/Fan nob on.

Unfortuantly, I was not able to get my hands on the VAG tool to see if the switch was telling the compressor to turn on.