A/C problem, not taking freon in the system

**daggydagg** · 07-23-2013 01:58 PM

Hello guys, i just got back from the shop today and tried to get my a/c fixed and recharged. I replace the receiver drier as i was told to do because the system is not taking the freon charge in the low pressure. So i replace the drier and still the a/c is not taking charge and stuck on econ light... The heater still work so i doubt it's the compressor... What else should i check or replace? Expansion valve???? Need some tip guys..... Thanks....

**airbornerifleman** · 07-23-2013 02:06 PM

do you physically see/hear the compressor operating?

**daggydagg** · 07-23-2013 02:07 PM

how can i hear it operating? where to listen? i mean the heater work, and it blows hot air.... but when i out it to low the a/c dont work and stays on econ... can't even charge the ac....

**aluthman** · 07-23-2013 02:25 PM

The heater and HVAC fan both operate independently of the A/C compressor. The fact that they work tells you nothing.

**daggydagg** · 07-23-2013 02:30 PM

Originally Posted by aluthman

The heater and HVAC fan both operate independently of the A/C compressor. The fact that they work tells you nothing.

so what should i do? should i replace the expansion valve first?

**daggydagg** · 07-23-2013 02:31 PM

If the expansion valve is the problem, what does it do? I mean how can you tell if the expansion valve is the problem?

**CorneliusRox** · 07-23-2013 02:44 PM

You only fill from the high side. I dont remember why, but that is how it is done.

Make sure the orings behind the compressor are good, and the valves (usually rebuild-able) are changed. By valves I am talking about the fill ports. They are basically the same cores as in valve stems.

Then the air dryer has desiccant material in it that if it is exposed to anything other than a closed system for more than 30min, it is junk and needs to be replaced.

I would start with those because the compressor, condenser, and evaporator are almost never the real issue.

**daggydagg** · 07-23-2013 02:50 PM

Originally Posted by CorneliusRox

You only fill from the high side. I dont remember why, but that is how it is done.

Make sure the orings behind the compressor are good, and the valves (usually rebuild-able) are changed. By valves I am talking about the fill ports. They are basically the same cores as in valve stems.

Then the air dryer has desiccant material in it that if it is exposed to anything other than a closed system for more than 30min, it is junk and needs to be replaced.

I would start with those because the compressor, condenser, and evaporator are almost never the real issue.

I'm in Europe, I mean these people should know how to fill the car. But the drier was replaced and still didnt take any coolant. the hose was plugged in the high and low side earlier.

**CorneliusRox** · 07-23-2013 03:24 PM

Originally Posted by daggydagg

I'm in Europe, I mean these people should know how to fill the car. But the drier was replaced and still didnt take any coolant. the hose was plugged in the high and low side earlier.

I would definitely start by replacing both of the fill valves (like $3 for a kit with new cores and a tool). Then if it still doesnt fill, I would assume that the machine they have sucks because nothing should be blocking a line, and if there was something and you were filling from high and low, it would still take the r134a, it just wouldnt work afterwards.

**daggydagg** · 07-24-2013 01:14 AM

Originally Posted by CorneliusRox

I would definitely start by replacing both of the fill valves (like $3 for a kit with new cores and a tool). Then if it still doesnt fill, I would assume that the machine they have sucks because nothing should be blocking a line, and if there was something and you were filling from high and low, it would still take the r134a, it just wouldnt work afterwards.

Is there a DIY or where these are located? Do you happen to know where the expansion valve and o ring located?

**daggydagg** · 07-24-2013 01:15 AM

Originally Posted by CorneliusRox

I would definitely start by replacing both of the fill valves (like $3 for a kit with new cores and a tool). Then if it still doesnt fill, I would assume that the machine they have sucks because nothing should be blocking a line, and if there was something and you were filling from high and low, it would still take the r134a, it just wouldnt work afterwards.

Is there a DIY or where these are located? Do you happen to know where the expansion valve and o ring located?

**fly300kts** · 07-24-2013 04:43 AM

There is no expansion valve on the A4, just a calibrated orifice
Not like others, I think your compressor is shot

Phil

**CorneliusRox** · 07-24-2013 07:07 AM

Originally Posted by fly300kts

There is no expansion valve on the A4, just a calibrated orifice
Not like others, I think your compressor is shot

Phil

I didnt know that. Regardless, I dont think a blown compressor would stop r134a from going into the system. Maybe the A4 should have gone with the standard style AC because my 97 truck blows colder than the A4, fresh charge in both.

**mcpcartier** · 07-24-2013 07:57 AM

Good info Corey,

Already feel a little smarter today....my daily education from AZ.

Originally Posted by CorneliusRox

You only fill from the high side. I dont remember why, but that is how it is done.

Make sure the orings behind the compressor are good, and the valves (usually rebuild-able) are changed. By valves I am talking about the fill ports. They are basically the same cores as in valve stems.

Then the air dryer has desiccant material in it that if it is exposed to anything other than a closed system for more than 30min, it is junk and needs to be replaced.

I would start with those because the compressor, condenser, and evaporator are almost never the real issue.

**daggydagg** · 07-24-2013 01:30 PM

Originally Posted by CorneliusRox

I didnt know that. Regardless, I dont think a blown compressor would stop r134a from going into the system. Maybe the A4 should have gone with the standard style AC because my 97 truck blows colder than the A4, fresh charge in both.

I agree, if the compressor is shot why is it not taking r-134? and the heater is working.. even the defroster's are working fine, it's just not taking r-134. here is what i found online and it is a expansion valve for a4 i suppose. http://www.amazon.com/Santech-Air-Co...xpansion+valve

**schirm** · 07-24-2013 01:47 PM

My heater worked fine when my AC did not work. My compressor was shot.

**CorneliusRox** · 07-24-2013 02:16 PM

Originally Posted by mcpcartier

Good info Corey,

Already feel a little smarter today....my daily education from AZ.

Glad I could help!

Originally Posted by schirm

My heater worked fine when my AC did not work. My compressor was shot.

Maybe compressors fair more often on VW/Audi's? 90% of my AC experience is with US cars. I still cant wrap my head around why it wouldnt accept r134a though.

**slimmj0k3r** · 07-24-2013 03:12 PM

if you have vag-com check for codes. My AC system threw a code when I put the car together because i started it without plugging something in. It was plugged in afterwards but I never cleared the code and my system would not take the freon.

**Brillo** · 07-24-2013 03:37 PM

AC system is charged at the low pressure valve, not the high pressure side. Otherwise you would never be able to get any coolant into the system. You need to determine if the compressor is turning. If not you may have no pressure in the system and a pressure switch will deactivate the compressor clutch in which case you need to pressurize the low pressure side of the system to get the compressor working. Once it starts working the system will allow more coolant to enter the system. If the compressor is shot obviously you will never be able to charge the system, and you will need to install a new one. check the appropriate fuses before doing anything else. Also, if the system is at ambient pressure you wasted your money on a dryer and you will need a new one installed (because it is contaminated) and the system will have to be pumped down to a proper vacuum before it can be recharged.

**AbigFern** · 07-24-2013 05:00 PM

Fill from low side , compressor has nothing to do with heat check climate control module for codes

**CorneliusRox** · 07-24-2013 05:53 PM

If you are using a can from AutoZone, I guess they want you to use the low pressure side.

If you are using a machine and you drain the system, add vacuum, add oil, and the r134a, your machine should be able to charge from high, low, or both, but the correct way (based on the instructions on any machine manual) usually is to charge the high side. You probably need a vacuum to do so, so that is probably why an AutoZone can can't do high pressure.

**daggydagg** · 07-25-2013 10:22 AM

I am in europe so these guys should be able to know audi on top of their head.... Thats another reason i can't wrap around my head, is why the system is not taking r-134a????? I am in belgium and i believe that the place that i took the car to see's audi pretty much more than a shop in the US. Thank's for the help....