Another A/C failure

[B5A4coastie]

No codes and everything else seemed to work fine, beside blowing warm/hot air, so I replaced the orfice tube. It was pretty dirty, but not the reason for my a/c to quit.



Here’s what VDCS shows.





I’m thinking my compressor clutch isn’t engaging. It’s hard to see what’s going on under there, but I can’t tell a difference in engine idle when I turn on the a/c. I’m running to the store now, so I’ll test throttle response with the a/c on and see if there’s any change. In the mean time, please throw your suggestions my way.

[Audibot]

Mine failed suddenly just like yours. It worked perfectly the evening before; next morning, nothing. IIRC, these compressors are clutchless; there is a solenoid that changes the angle of the swoish plate to actuate the compressor pistons. When a/c is off, the position is parallel to the pulley rotation so no work is being done. When it engages, the angle of the plate moves to compress the refrigerant. The angle can be varied to provide more or less cooling.

1st suggestion: Visually check the refrigerant pressure switch on the driver's side of the condenser. You can see it with the hood popped open, somewhere by the headlight. If it looks like it's dirty/oily, that means the o-ring has gone and bled all your refrigerant out. This happened to me a ways back. Replaced the o-ring, recharged the system, and was good to go. If the pressure is too low, the system is not engaging.

2nd suggestion: Read the pressure of the a/c system. A shop can do this for you if you don't have the gauges. Sometimes those cans of R-134a have a gauge. In any case, if the pressure is too low, the system won't start. Will give you a decent indication if there's enough refrigerant in there and something else has broken.

3rd suggestion: Replace the compressor. I got my replacement from discountacparts.com. Came with brand new Denso compressor, PAG oil, o-rings (didn't need), accumulator/drier, and orifice tube. A shop can evacuate the system for you prior to doing the work (it's pretty simple and straight-forward to do after taking the bumper off). After it's done, go back to the shop to have it filled.

[B5A4coastie]

Very in depth reply, thank you!

According to the gauge on a recharge bottle there’s 50psi (high green). Shouldn’t you see a code if there’s low refrigerant? (Econ light maybe)

I’ll put eyes on the switch tomorrow.

[wootwoot]

OP you mentioned another time that your AC failed. How long ago was that and what was the cause?

[B5A4coastie]

OP you mentioned another time that your AC failed. How long ago was that and what was the cause?

I just titled the post that way because it’s a trend during this time of year. Last year I had to charge my a/c with a bottle of Freon, but that was it. I’ve only had this car for a year now, so I can’t give you much more of a history or timeline.

[Audibot]

Sounds like you have a slow leak.

When my o-ring blew, I was just embarking on a road trip. Didn't know it happened until the next day when the a/c wouldn't work. Thankfully it was slowly leaking out. So I basically grabbed a few bottles, charged them up, and drove (got to my destination next day); same on the 2-day trip back.

After I got, I saw the o-ring, and pulled off the bumper to replace it. Thankfully my Dad has an a/c manifold kit and vacuum pump, so I totally evacuated the system before charging it.

[B5A4coastie]

It’s holding pressure at 50 psi right now

[Audibot]

Bunch of random thoughts:

1. When you changed the orifice tube, did you, by chance, vacuum out the system and then refill it? I wonder if it starts to work and then the evaporator freezes? Would need pressure readings on high side (G65, in bar) to know more. High side, IIRC, should be between 150 and 250 psi (10-17 bar). Maybe as high as 30 bar but I think that's too high. Low side should be between 30-50 psi while running.

2. Have you checked the o-ring on the pressure switch?

3. Also, thought of this now--are the fans up front switching on? Both electric fans need to be on and working for the system to come on. If they are not running, you may need to verify the fans are operational--can do this by unplugging them from the fan control module and jumping them to the battery--should start to spin right up.

4. System pressure at rest should be >50 psi (3.5 bar). I think mine was pressured to ~90 psi (6 bar) when the system was off (like first thing in the morning). There is a minimum low pressure required; below this, the system won't run to protect itself.

5. To answer your question, I don't recall seeing an econ light when my compressor went. I did my due diligence in checking out the other components as they are far cheaper than replacing a compressor. If you DO end up needing a compressor, I bought a brand new Denso kit from discountacparts.com (came with compressor, PAG oil, accumulator/drier, orifice tube, and o-rings). At the time was the cheapest one I could find new (not sure about now).

[B5A4coastie]

I haven’t dug much deeper in this yet. I’m currently at the hospital, waiting for our first baby to make his introduction. He’s taking his time!

I’ll have to look into the other components. I don’t remember what the state of the fans were.

I didn’t have the system completely evacuated. Just bled the low side and popped the filter in. Not the best move for the planet I know, but I didn’t think about how that may affect the system.

[Audibot]

Congratulations! I pray the delivery process goes smoothly for the both of you! Definitely take care of your family first!

[Kingzilla17]

Bunch of random thoughts:

1. When you changed the orifice tube, did you, by chance, vacuum out the system and then refill it? I wonder if it starts to work and then the evaporator freezes? Would need pressure readings on high side (G65, in bar) to know more. High side, IIRC, should be between 150 and 250 psi (10-17 bar). Maybe as high as 30 bar but I think that's too high. Low side should be between 30-50 psi while running.

2. Have you checked the o-ring on the pressure switch?

3. Also, thought of this now--are the fans up front switching on? Both electric fans need to be on and working for the system to come on. If they are not running, you may need to verify the fans are operational--can do this by unplugging them from the fan control module and jumping them to the battery--should start to spin right up.

4. System pressure at rest should be >50 psi (3.5 bar). I think mine was pressured to ~90 psi (6 bar) when the system was off (like first thing in the morning). There is a minimum low pressure required; below this, the system won't run to protect itself.

5. To answer your question, I don't recall seeing an econ light when my compressor went. I did my due diligence in checking out the other components as they are far cheaper than replacing a compressor. If you DO end up needing a compressor, I bought a brand new Denso kit from discountacparts.com (came with compressor, PAG oil, accumulator/drier, orifice tube, and o-rings). At the time was the cheapest one I could find new (not sure about now).

Jumping in for a questing as you have swapped out the compressor. Ill be swapping this in with a used compressor I just ordered from a fellow member. Question is after you replaced the compressor, what other parts did you replace? I haven't had luck finding a solid DIY for the swap but I would assume its straight forward. My only thing is knowing what other parts I have to swap when I do this. Some say the orifice tube and drier are a must while other dont mention it and say the only requirement is to flush the system before.

[Audibot]

Jumping in for a questing as you have swapped out the compressor. Ill be swapping this in with a used compressor I just ordered from a fellow member. Question is after you replaced the compressor, what other parts did you replace? I haven't had luck finding a solid DIY for the swap but I would assume its straight forward. My only thing is knowing what other parts I have to swap when I do this. Some say the orifice tube and drier are a must while other dont mention it and say the only requirement is to flush the system before.

The replacement is VERY straightforward, once the front bumper is off. Make sure the system has no refrigerant in it before you start. The compressor was held in by 3 bolts, IIRC, and they are pretty accessible underneath. All the a/c hoses are held in with hex screw and are easy enough to separate off. I used an adjustable on the the low side hardline, where the orifice tube is.

I swapped out all the components that came with the kit, except the o-rings, as they were all fine. So compressor (which I filled with oil before install), the orifice tube, and, lastly the accumulator (to minimize the amount of water absorbed by the desiccant. Be sure to oil the o-rings lightly to assist with install.

Before I did any of that, with the lines opened, I removed the accumulator and orifice tube (which didn't show much of anything in the way debris). I had purchased some a/c line cleaner off Amazon, and used a funnel to pour it into the lines. I let it sit a bit and then blew it out with an air compressor. This got any residual oil, dirt, and debris out of the system. I did it through the lines that connect compressor to condenser, condenser to accumulator, accumulator to orifice tube, and orifice tube to evaporator.

After it was back together, I immediately had a high vacuum pump (from HF) on it (via a/c manifold gauge kit; also from HF), and left it on for about an hour. Got down to -29.x inHg before closing the valves off, taking off the pump, and connecting the cans of refrigerant (cans were weighed beforehand).
Once a can's worth was in (not full), turned on the car, set the a/c to the max cold settings, and emptied most of another can into it until the gauges read correctly.

I don't think the a/c was ever as cold since I had bought the car.

[Kingzilla17]

The replacement is VERY straightforward, once the front bumper is off. Make sure the system has no refrigerant in it before you start. The compressor was held in by 3 bolts, IIRC, and they are pretty accessible underneath. All the a/c hoses are held in with hex screw and are easy enough to separate off. I used an adjustable on the the low side hardline, where the orifice tube is.

I swapped out all the components that came with the kit, except the o-rings, as they were all fine. So compressor (which I filled with oil before install), the orifice tube, and, lastly the accumulator (to minimize the amount of water absorbed by the desiccant. Be sure to oil the o-rings lightly to assist with install.

Before I did any of that, with the lines opened, I removed the accumulator and orifice tube (which didn't show much of anything in the way debris). I had purchased some a/c line cleaner off Amazon, and used a funnel to pour it into the lines. I let it sit a bit and then blew it out with an air compressor. This got any residual oil, dirt, and debris out of the system. I did it through the lines that connect compressor to condenser, condenser to accumulator, accumulator to orifice tube, and orifice tube to evaporator.

After it was back together, I immediately had a high vacuum pump (from HF) on it (via a/c manifold gauge kit; also from HF), and left it on for about an hour. Got down to -29.x inHg before closing the valves off, taking off the pump, and connecting the cans of refrigerant (cans were weighed beforehand).
Once a can's worth was in (not full), turned on the car, set the a/c to the max cold settings, and emptied most of another can into it until the gauges read correctly.

I don't think the a/c was ever as cold since I had bought the car.

Perfect sounds straight forward as I thought. Ill go ahead and order the orifice tube and accumulator to be safe. I don't have access to an air compressor but will have the system flushed out before and then charged up after. Am I wrong to assume that ill be fine to drive the car with the AC turned off to the shop after replacing the parts so they can refill and charge or would that damage the compressor or any other AC components?

[Theiceman]

No problem. There is a clutch in the compressor that wont kick in without freon


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[Audibot]

It is perfectly fine. Probably a bit better to do the system evacuation and subsequent refill when it's hot because being hot will "bake off" moisture, allow it to be evacuated more rapidly. In space, we use heaters to do the same, although its an infinitely better vacuum.

No problem. There is a clutch in the compressor that wont kick in without freon

Our compressors are clutchless. They use a swashplate whose control is governed by the solenoid valve on the compressor, and whose activation is dependent on the G65 switch. Below is a nice teardown off a B6:

https://www.audizine.com/forum/showt...late-vs-clutch

[Theiceman]

Ah. Same thing though right ? Wont activate without pressure

Great link btw. Very informative.


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[B5A4coastie]

In space, we use heaters to do the same, although its an infinitely better vacuum.

I knew this was rocket science!

[wding2000]

Sounds like you have a slow leak.

After I got, I saw the o-ring, and pulled off the bumper to replace it. Thankfully my Dad has an a/c manifold kit and vacuum pump, so I totally evacuated the system before charging it.

So even if just change G65 o-ring, you have to evacuate, vacuum and charge entire AC system?

I have intermittent "stuck on ECON mode", usually after car parked outside and got hot. Next morning it is fine. Checked refrigerant pressure on low side 35-40 psi with AC running. After I refilled a can (350g), it seems still the same pressure - leak somewhere? Next, will do a UV dye check.

[Audibot]

So even if just change G65 o-ring, you have to evacuate, vacuum and charge entire AC system?

I have intermittent "stuck on ECON mode", usually after car parked outside and got hot. Next morning it is fine. Checked refrigerant pressure on low side 35-40 psi with AC running. After I refilled a can (350g), it seems still the same pressure - leak somewhere? Next, will do a UV dye check.

Possibly not. The G65 is a schrader valve (like a car or bicycle tire). The sensor presses down on a button to get gas pressure for a reading, but if you remove the sensor quickly enough, you shouldn't lose much gas (unless it's already escaped via the bad o-ring.

When I first lost pressure on mine, it lost enough pressure to reduce close to atmospheric but I was able to recharge it and it would last for a day. Next day, it'd be low enough not to work.

[pablolizarraga]

Since you have VCDS, check the shut-off codes. 3rd post in this thread.

https://www.audizine.com/forum/showt...-A-C-Diag-time

Not sure which measuring block but you’ll find it.

I initially weighed a/c cans to determine refill amount but it was not cold enough. Used the manifold gauges and the temperature/pressure chart to determine correct amount and its been icy cold since then.


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[wding2000]

Possibly not. The G65 is a schrader valve (like a car or bicycle tire). The sensor presses down on a button to get gas pressure for a reading, but if you remove the sensor quickly enough, you shouldn't lose much gas (unless it's already escaped via the bad o-ring.

When I first lost pressure on mine, it lost enough pressure to reduce close to atmospheric but I was able to recharge it and it would last for a day. Next day, it'd be low enough not to work.

Thanks

[wding2000]

Now I am 100% stuck on ECON mode. Will VAG-COM to see faulty parts. Also now the fan will not run - was running just fine. Is it due to AC not on? or I might have fan / fan control issues as well, aside from AC; or they are related?

[Theiceman]

Now I am 100% stuck on ECON mode. Will VAG-COM to see faulty parts. Also now the fan will not run - was running just fine. Is it due to AC not on? or I might have fan / fan control issues as well, aside from AC; or they are related?

Everything is interrelated with AC. kets see what vcds comes back with

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[wding2000]

I think it is faulty G65?

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 8E0-820-043.lbl
Part No: 8E0 820 043 BM
Component: A4 Klimaautomat 3233
Coding: 00000
Shop #: WSC 00000
VCID: 6D87C8156485C7FF45B-5160

1 Fault Found:
00819 - High Pressure Sensor (G65)
07-10 - Signal too Low - Intermittent

[pablolizarraga]

I think it is faulty G65?

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 8E0-820-043.lbl
Part No: 8E0 820 043 BM
Component: A4 Klimaautomat 3233
Coding: 00000
Shop #: WSC 00000
VCID: 6D87C8156485C7FF45B-5160

1 Fault Found:
00819 - High Pressure Sensor (G65)
07-10 - Signal too Low - Intermittent

I had same code, but i think it just indicates theres not enough pressure in the system. Replacing the sensor didnt help. One of your shut-off codes also confirms low pressure as well. Before you buy another G65 sensor, borrow an a/c manifold gauge from Autozone and check your system’s pressure.

https://youtu.be/QKmbO3rAd3Q

If it’s low, you may be lucky in trying one of those a/c cans to refill system. It worked for me once and a/c remained cold for a few years. This last time my a/c went into ECON mode, the compressor had grenaded itself so I replaced everything.


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[wding2000]

So 3 bars (with compressor off) is too low to kick off compressor?

[pablolizarraga]

So 3 bars (with compressor off) is too low to kick off compressor?

Yes.

IMG_7560.JPG


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[wding2000]

Yes.

Thanks. Not out of woods yet, but I have a rough idea what is going on.

Borrowed gauge and vac pump from Autozone, measured no refrigerant, pulled vacuum 27-28 inHg and it held for two hours (maybe slight drop to 26). I was excited of no leak (no so fast yet - see below), or only slow leak. I started adding refrigerant to 3.5 bars, AC still will not kick on. Then when engine off, I heard a gushing sound at driver side condenser / compressor area. It is not subtle leak but gushing sound. But I could not determine exactly where, without taking bump off. Could be pressure sensor o-ring, or some connections, hopefully not condenser. Sure enough, after some time, it drops to 2 bars, then eventually to 1 bar. Sorry to ozone layer.

It is super weird of one-directional leak, or maybe no leak at < 1 bar (vacuum), but leak at higher pressure. I tested fan, compressor, and checked relay - okay. Definitely leak, and maybe pressure sensor as well - I might just change it as well (and orifice and drier). Stay tuned.

[wding2000]

It is pressure sensor!

Pulled bumper off, pressurized to 60 psi with tire inflator (found a nozzle can fit), air gushing out of sensor; removed sensor, repeat, pressure held. Orifice tube is dirty, but not clogged at all, but cheap enough and will change. Parts in order.

[pablolizarraga]

Hopefully its just that sensor. Since your system is empty, it may be a good idea to at least change out the dryer as well. They’re pretty cheap and relatively easy to replace.


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[wding2000]

Hopefully its just that sensor.

Pressure tested after removing faulty sensor - pretty sure it is just that.

[B5A4coastie]

Sorry for the late response. Low pressure is still holding, the pressure sensor is clean and dry. I have 12v to the module, but I don’t think anything is coming out of it. I tried to jump the 12v at the module to the fans with he ignition on, but car off and nothing happened, but the more I think about it, there may not me much amperage with the car off. I’ll try again from the battery, but I wanted to be sure we’re all jumping at the same spot. I didn’t see any “connectors” for the fans. They are soldered at the module and then attached at the fans. Do I need to be in the service position fo this test?



I have positive 12v on the lead closest to the radiator and no pathing else on any other lead. I didn’t try to start the car and test, since the pull was so close to it.

[B5A4coastie]

Verified that both fans are operational, I guess I’m looking at a compressor.

[Audibot]

Probably. Funny enough, my brother's A/C isn't working in his GTI. No ECON or anything. Light shows just no a/c. I scanned it yesterday and found that the car is specifying something like 0.850 A to the compressor and the compressor isn't actually outputting anything. So it's either an issue with his clutch or the actual connector (which isn't in the best shape)

Wondering if it's similar for yours. As a reminder, the pre-2007 A4s have a clutched compressor; the 2007-2008 are clutchless.