AC not working after refill

[TheClient]

Low pressure side, to evap should be cold lines if compressor and refrigerant are operating. If the regulator valve was not operational, it would mean the compressor is not really pumping little or any refrigerant, so not cold. But same problem would exist if there was another severe failure inside the compressor based on my understanding of things. Waits to be corrected.......

[Inex]

Okay, makes sense.

 

I am tempted to try swapping the valve but I am not sure if any valve would fit...

[Breezy_Pete]

Isn't compressor to evaporator the high pressure side?

 

Did you look to see if all parts of the pulley are rotating as one?

Just occurs to me that although VCDS says the compressor is rotating at 1000rpm for idle engine revs, that may well be a calculated rather than measured value.

[TheClient]

Anything after the Ex Valve it should be low pressure, through evap and back to compressor.

[Inex]

Ok so after 8 days of vacation, the car has been sitting and today I drive about 100km today to find out there is a slight hissing/howling noise coming from the vents (Econ on). 

 

As I keep turning things on and off to figure out where it comes from I notice the sound gets stronger when I turn Econ off. Air blows pretty cold but can't tell as ambient temp is pretty low too...  

 

So I pop the hood and check those ac lines again. This time the thick one is cold, maybe not freezing cold but cold...

 

Spent the day thinking about this and I have a feeling the AC circuit might be clogged up somehow... Is that even possible? If so, does anyone know how to check it before I swap parts out? I do have a pressure sensor ready to exchange and I did not run a scan on it today as of yet... 

[Inex]

Could it be a problem with the evaporator? 

 

Looking at what the AC circuit explained in the video below.... I can only assume the evaporator is not doing a good enough job for the air to be blown into the cabin.

 

Reasons for believing this:

-There is no compressor shut off code

-There is no fault code in the HVAC system

-There is a difference in load for the aux belt (noticeable when turning on the AC, the engine vibration pattern changes slightly)

-The low-side line is very cold (not freezing cold)

 

So in other words, the refrigerant circuit is complete but there might not be enough evaporation going on due to bad evaporator? 

How big of a job is it to reach the evaporator and check it out?

 

 

[TheClient]

As I've said along the way, I'm no expert but I expect it is more likely a compressor which is not pumping enough refrigerant.  Is there any specialist where you could take it? You would need to get it evacuated and then refilled there anyway if you replace the compressor?

[Inex]

Unfortunately a specialist garage would charge me way over my budget here in Denmark...

 

I was hoping I could get close to figuring it out what the issue is myself and then have my own non-specialist mechanic do the necessary work but I guess it doesn't work that way with AC systems.... :(

[Inex]

Swapped out the pressure sensor today and still - no change....

 

I am looking into getting a thorough diagnostic from a specialist next week if I have the time...

 

At the moment:

-compressor is running

-fan is running

-low pressure line is cold

 

 

I did notice one thing after I changed the sensor.... The Auto button will only turn off when manually adjusting the blower speed. is this normal? Can anyone check on theirs please? If I remember correctly - while AUTO is on, if you press it, it should go to OFF. I was hoping this would be fixed once I erase the codes but its still the same

[TheClient]

On my vRS climate control there is an Auto button with two modes.  I can only turn it off by adjusting fan speed too. Text out of user manual below:

 

Auto Mode

 

If the warning light in the top right corner of the button lights up, the
Climatronic operates in “HIGH” mode. The “HIGH” mode is the standard setting of the
Climatronic.

When pressing again the button , the Climatronic changes into the “LOW” mode
and the warning light in the top left corner lights up. The Climatronic uses only in this
mode the lower blower speed. However taking into account the noise level, this is
more comfortable, yet be aware that the effectiveness of the air conditioning system is
reduced particularly if the vehicle is fully occupied.

By pressing again the button , you change into the “HIGH” mode.
The automatic mode is switched off by pressing the button for the air distribution or
increasing or decreasing the blower speed. The temperature is nevertheless
regulated.

Edited 16 June, 2017 by TheClient

[Inex]

On 6/16/2017 at 19:04, TheClient said:

On my vRS climate control there is an Auto button with two modes.  I can only turn it off by adjusting fan speed too. Text out of user manual below:

 

Auto Mode

 

If the warning light in the top right corner of the button lights up, the
Climatronic operates in “HIGH” mode. The “HIGH” mode is the standard setting of the
Climatronic.

When pressing again the button , the Climatronic changes into the “LOW” mode
and the warning light in the top left corner lights up. The Climatronic uses only in this
mode the lower blower speed. However taking into account the noise level, this is
more comfortable, yet be aware that the effectiveness of the air conditioning system is
reduced particularly if the vehicle is fully occupied.

By pressing again the button , you change into the “HIGH” mode.
The automatic mode is switched off by pressing the button for the air distribution or
increasing or decreasing the blower speed. The temperature is nevertheless
regulated.

Thanks - I just had a moment when I thought something changed.

 

 

I took the car to another garage where they found on the pipe where the pressure sensor is (between the compressor and the condenser). Aparently that first garage screwed me over and either did a ****ty job refilling or they just lied..... 

 

Anyhow, I had this garage confirm to me that the compressor is healthy and that there is no other leak other than this.

The original pipe from VW costs around 350 pounds and it is almost impossible to find on a scrappy (in Denmark at least). However, I found a new one on Ebay from Poland for 45 pounds which is on its way. 

 

Finding a cheaper new one, knowing the compressor and the rest are fine and knowing they can change the pipe without taking the entire front-end off pushed me into deciding to fix the car.

[TheClient]

Well, that sounds like a good result.

 

Fingers crossed for the correct part fitment.  I have to say, it was sounding suspiciously like a dead compressor to my rudimentary AC knowledge mind, but it was just low refrigerant all along!!!  Not sure at all what the other Garage was doing, as that was the reason we collectively discounted low refrigerant, maybe just not paying attention.. Or the leak got worse after recharge? Who knows....  

[Papfox]

That sounded exactly like the symptom when my compressor died. When it was cool outside, the AC worked fine and got cold but, as soon as I left the car out in the sun, no cooling until I'd driven for about 6-10 minutes.

[Inex]

Back on this story again. 

 

I had the faulty pipe replaced and the system re-gassed and everyone was happy - AC was working.

It worked flawlessly for 2 and a half days till one evening when I start the car and I hear that hissing sound again in the cabin from the vents.... With the AC still working, I drive around, mind my business and every now and then the AC would stop blowing cold and the hissing sound gets louder and quieter randomly. 

 

Around 350 km later, I go back to the shop and tell them about it. They hook the vcds up and see there is an intermittent lower limit exceeded error. Fine, they check with the UV light again and see no trace of leaks. They hook the AC machine up and do a pressure test - all good. They vacuum the system and figure out it was missing about 135g since it could only recover 390 out of 525g. 

 

Finally they fill it up again and the hissing is gone but again, no trace of leaks and AC works perfectly..... They said I should return if it happens again... I sure hope they just filled it up to the wrong amount and there is no other leak... :(

 

This is, however, the last AC intervention I will ever be doing on any of my cars..... The costs are already almost as high as any other big job on the car.... getting close to timing belt or clutch territory. I can only imagine it would double up if they have to fix another leak as anything else other than that pipe is hardly accessible... NEVER buy a car without a functioning AC system under the presumption that it just needs a re-gas  lesson learned.