2006 Jetta A/C issues

[pawdiwagon]

I have owned a duramax for years and was so thrilled with it that I could hardly wait to get my hands on a tdi jetta for a little commuter rig. I nabbed a 2006 last week and my excitement was quickly stifled when I was driving it from where I bought it in Arkansas down to San Antonio and noticed on one occasion that the A/C was blowing pretty warm air. Normal operation returned shortly and was fine the rest of the trip. However the next time I drove the car after arriving in San Antonio A/C was MIA. First thing I did was check the cabin air filter which was awful. I replaced it and then thought I'd check the charge. I used to work residential heat and air but I don't have any equipment for auto so I just picked up a cheapo recharge kit and hooked it up. Since I know everything about everything (sarcasm) I assumed that since the compressor shaft was spinning that it was ...well, compressing stuff. and the charge was on the high side of 100psi on the low side port. Which in retrospect is probably impossible. Thinking possibly the old owner had tried to compensate for his dreadful cabin filter by shoving more refrigerant in it I proceeded to vent it down in an environmentally friendly fashion. Obviously (now) the compressor was not loaded and now I have no clue where my refrigerant charge is. Here is my thoughts so far.

All A/C related fuses check good.

Fan operation seems normal. Both run at the same time and turn off and on with A/C button once the car is good and warm.

Replaced Pressure transducer in the refrigerant line just behind the radiator/condensor.

I did recharge as much as the can would push into the system. I also caught the silly thing cooling once when it didn't know I was looking and I was able to shove the remainder of the can in there, but only about 35 psi worth with a VERY hot cabin. Point being, it is low on charge but not enough that it should be locked out from high/low pressure. Also the compressor seems to still be able to go about its compressing ways when it feels the desire.

Everything in my low information brain points to my RCV (which is on the way). I thought my days of cracking refrigerant lines were behind me. but I'm far to big of a cheap skate to pay someone else to do it for me.

I don't have access to VCSD, maybe I should invest. it would be nice to know that the RCV is receiving a call from the computer.

I know from what I've read that RCV usually is an intermittant service or delayed start scenario. sadly I have no prior experience with the car to know if this is the case. I contacted the former owner about it and not surprisingly, he said he never had any issues.

So is there anything else that I should be checking here or something that I've missed? Do you all think I'm on the right path? My viking blood is melting in this stupid texas heat. I truly appreciate any and all helpful feedback!

 

[Andrewh]

I think you threw the wrong parts at it.
I would have guessed at something else if it still had a charge.
my guess is it is now over charged.

First thing I would have checked is the blend doors.
see if an actuator died.

I would probably take it in or find the right charge and drop it back down. I don't know if you can damage it if the high pressure switch didn't trip yet, but not sure.

This is my recommendation.

In the current condition I am not sure you can test, but if I wanted to verify the blend door, I would try running a/c when the car is cold first with recirc on and see if you get a/c air. of course you have the a/c delay too and depending on how hot it is outside you might not feel it before the water temp comes up.
you could also clamp off a heater hose and see if it comes back as well.
but in an over charge condition, I am not sure it will work.

I own a 2006, but have not tinkered with the a/c in that. I installed an aftermarket a/c system in another car, and tinkered with other newer cars, just not the tdi specifically.

 

[pawdiwagon]

It is definitely not over charged at least if this gauge isn't lying to me. The 100+ psi was the static pressure and that was before the charge was adjusted (down). The one time I caught it running it was undercharged and I didn't have enough refrigerant to get it fully charged. My thought with replacing the pressure transducer was that maybe the system was locked out due to a low charge scenario or a faulty transducer. When the compressor was loaded I could hear the txv hissing away which from my heat and air days was indicitive of the txv not getting a solid column of refrigerant.

I did think of the blend doors but it's ambient temperature not hot, and cycling the thermostat hot and cold demonstrated what truly hot air feels like. not a very technical shakedown but I'm thinking that the compressor not loading would definitely be the issue.

 

[DanG144]

The most likely issue is the RCV, refrigerant control valve. These cars are notorious for them failing and causing the symptoms you have.

Catch it when it is cooling (or get VCDS) and see if the fans are operating. Both should operate together.

Best would be to borrow a VCDS. San Antonio has quite a few guys on this site, so post in the area forum:http://forums.tdiclub.com/forumdisplay.php?f=76

or look for the VCDS share sites, one such is:http://forums.tdiclub.com/showthread.php?t=296841

To really nail it down, use a set of gauges and VCDS. Though VCDS is pretty good all by itself.

Some MK V info:
http://forums.tdiclub.com/showthread.php?t=253641

A bit about the RCV.
http://forums.tdiclub.com/showthread.php?t=284611

VCDS data:
http://forums.tdiclub.com/showthread.php?t=461016

 

[pawdiwagon]

Thanks for weighing in danG144. I read through the links that you posted. It seems the map is down for the vcds locator. I did go to the region link and found a local service guy and called him. He said they are booked out a couple of weeks and he would have to charge me to hook up to my rig unless I had him do the repair. He was very nice about mentioning some of the things to keep an eye on with the car and also mentioned that he has found the failure rate on the replacement RCV to be really high so he has just been putting new compressors in. I'm assuming he is working on the notion that the valve gets fouled with contaminants that are already in the compressor and simply replacing the valve will only provide temporary solution. You seem to have seen a number of these. Is this your experience as well? I have a new one on the way anyway and will likely see if i can clean the OE one to keep as a spare. It will be nice if I can at least nail down for certain that I have found the issue and will at least be able to experience the symptoms of the failure process if it goes out again. If these things pull into a good vacuum in 45 minutes that's not a big deal to work and rework if it buys me a little more time to recover from the financial pinch of just having bought the car with cash.

 

[pawdiwagon]

I would eventually want to pick up a VCDS. what's the best way to go about getting one? If nothing else the car doors don't automatically unlock like my b6 audi when i remove the key from the ignition, I'm of the understanding that Vag-Com would enable me to sort that little issue right out. It would be nice to help others out if I picked one up too. I'm pretty sure trouble shooting with someone else's money is my own special take on livin' the dream!

 

[meerschm]

http://www.ross-tech.com/index.html

 

[pawdiwagon]

I Performed the RCV swap yesterday afternoon. I didn't notice any signs on the old part that there was excessive crud circulating in the compressor. Once I pulled a good vacuum and got the system recharged it was cooling just as it was supposed to. Once I had the system working, I swapped the original pressure transducer back on and the system continued to work flawlessly so that went back to autozone along with the loaner manifold/gauges and vacuum pump.

For anyone wishing to DIY without any A/C experience and minimal tools available I will provide some more details. I charged the system with an 88* F ambient temp and a medium load in the cabin (cloudy day, heavy tint) Final gauge pressures were 180/47psi A hotter day will drive High side up (although minimally I would imagine since it has a variable fan on a sensor) and a hot cabin would drive the Low side pressure a bit to the high side, be sure the blower is set to high when checking your charge. Of course there are more variables but that should get you in the general vicinity. You can also use the redneck rule of thumb of "shove refrigerant in it until the Suction line is beer can cold." I would advise that you may want to keep a cold beer nearby during the procedure...for reference.

Also. If I were to do the swap again, I would drop the fan assembly because it is all but impossible to get the valve out with it in place, which I didn't realize until I released the valve. I had left about 10psi of pressure in the system and if I had been able to get the new valve in place before the system finished off-gassing (3-5 seconds) I wouldn't have bothered to pull a vacuum before recharging. although it really wasn't that big of a deal to pull one anyways. If you wish, you can check to see if you performed the swap fast enough by depressing one of the shraeder valves at the service ports to see if there is any pressure left after the RCV is in place. This I say not knowing if there is any sort of a refrigerant check valve in the compressor that could leave pressure in the lines but not in the compressor itself. Safest bet is pull a vacuum. As it was I had the system open for about 15 minutes and pulled a vacuum for just over an hour while I was working on some other stuff.

Tools I used

Loaner manifold/gauges
Loaner Vacuum pump
90* snapring pliers
small flathead screwdriver for releasing electrical connectors (RCV,Fan assembly) as well as releasing the valve once the snapring was removed.
Rachet and t30(?) torx bit for removing the fan assembly.
putting the car on ramps gives plenty of access for my 270 lb self.

Parts

RCV
1 full 12.5 oz can and part of the second can of r134a refrigerant. I used a refrigerant for the partial can that included oil to compensate for what I might have lost in the swap.

It was a pretty painless task and well worth it now that the system is working again. If anyone sees any issues with my advice or procedures please weigh in and correct me so others don't follow my bad example. I wrote out my procedure in hopes of helping people and not to try to make myself feel smart. I realize a proper charge should be balanced with superheat and subcool values but I have no temperature clamps or data to charge it by and am too broke to buy equipment and waller in minutia when I will hopefully never have to work on an automotive A/C system again. Good luck to all and I will post back on this thread if the part does indeed fail again like the local shop advised that it would.