R134A Low
#1
R134A Low
Hey Guys,
I have a 2016 Q5, I put gauges on the low pressure port and got a reading to 25 psi with the A/C system running on max.
The system probably needs a top up.
The label under the hood says the vehicle needs R134A. Problem is in Canada you cant get R134A.
Any suggestions?
Thanks
I have a 2016 Q5, I put gauges on the low pressure port and got a reading to 25 psi with the A/C system running on max.
The system probably needs a top up.
The label under the hood says the vehicle needs R134A. Problem is in Canada you cant get R134A.
Any suggestions?
Thanks
#2
AudiWorld Super User
Is the 2016 still under warranty?
If so, I would strongly suggest taking it to a dealer. AC systems don't just lose gas pressure, something is leaking and unless that leak is found and fixed (which can be a tricky or expensive process) you're just going to need more gas every year or so as the leak gets worse. Plus, every time the hot gas condenses (i.e. when you shut the system after using it) it will be sucking in outside air and moisture, and that can form acids that literally eat the entire system out from the inside.
By all means top it up, if you just need to "get it home". But an AC leak really needs more attention than that. If the warranty service is two hours away, it is STILL going to be worth making the trip. I'm US-EPA certified to maintain car A/C systems, I can tell you they can be nightmares to properly diagnose, simply because so many of the parts are inaccessible.
If so, I would strongly suggest taking it to a dealer. AC systems don't just lose gas pressure, something is leaking and unless that leak is found and fixed (which can be a tricky or expensive process) you're just going to need more gas every year or so as the leak gets worse. Plus, every time the hot gas condenses (i.e. when you shut the system after using it) it will be sucking in outside air and moisture, and that can form acids that literally eat the entire system out from the inside.
By all means top it up, if you just need to "get it home". But an AC leak really needs more attention than that. If the warranty service is two hours away, it is STILL going to be worth making the trip. I'm US-EPA certified to maintain car A/C systems, I can tell you they can be nightmares to properly diagnose, simply because so many of the parts are inaccessible.
#3
AudiWorld Member
2016 should still be under warranty unless you have very high km's for the year. What made you put the gauge on the car? was the AC not blowing cold? I would see the dealer for sure.
#4
Thanks for the reply guys.
The vehicle is under warranty and when I took it to the dealer they said A/C is normal wear and tear like brakes. I do not agree with this. But I will take it back and get them to do a diagnostic which should show a problem with the system. This problem is not normal for a two year old vehicle.
I put the guages on because I have charged my A/C before. But I realized that Audi uses R134A which I can't get and the system is charged by volume not just by pressure. Because of this I decided not to charge it myself.
Hopefully the dealer fixes this problem at no cost fingers crossed.
Thanks again.
The vehicle is under warranty and when I took it to the dealer they said A/C is normal wear and tear like brakes. I do not agree with this. But I will take it back and get them to do a diagnostic which should show a problem with the system. This problem is not normal for a two year old vehicle.
I put the guages on because I have charged my A/C before. But I realized that Audi uses R134A which I can't get and the system is charged by volume not just by pressure. Because of this I decided not to charge it myself.
Hopefully the dealer fixes this problem at no cost fingers crossed.
Thanks again.
#6
AudiWorld Member
So just taking a quick look here, It looks like they do test the AC system for pressure with VCDS (there equivalent anyway) So it seems like a simple test they could do in about 30min. "A" dealer should be able to help you.
It looks like you don't check the pressure the old way with these new cars..
Where are you located?
It looks like you don't check the pressure the old way with these new cars..
Where are you located?
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#9
AudiWorld Super User
I'll back up all the way to start. Thus, pressure reading from gauge is doesn't tell you much without adjusting it for ambient temp. The lower the ambient temp, the lower the reading should be. It looks like that gauge face may be twistable in some way to get the blue and red shaded areas to line up. You also would need the Audi pressure specs; a generic gauge face doesn't really tell you that except rules of thumb.
AFAIK Audi's just use a high pressure limit switch, as opposed to one reading the pressure level in general. Thus no VCDS help on pulling pressure readings. The switch itself can fail, which cuts out the AC. VCDS would tell you if there is a sensor error or apparent misread. VCDS will also tell you compressor duty cycle; they don't use the old fashioned clutch that clicks.
Audi's do lose refrigerant, but not in two years to point of system malfunction. They shouldn't, but in practice small leaks often go unnoticed and folks skip over until system starts to falter. On the D3 A8's for example that are now 8 to 14 years old, many of us are seeing it lose enough that by 6 or 8 years the system is starting to basically no longer work. The fill weight on those though is very small by old stds. (630g); don't know what it is on Q5. Once it drops by half, system doesn't work, which on that model is then only about 11 oz. by weight.
The simple likely fix is to recharge it. Don't use the can crap since you have no way of knowing what is in there fill wise, or if properly filled back when it was built. If overfilled, you can blow compressor with time, which then costs you 100x the seemed-like-a-good-idea-at-the-time can gig. It sounds like maybe you can't buy it as a consumer in Canada anyway.
Instead, go to an AC repair place. you do not need a dealer for some special "Audi magic" on what underneath is a pretty standardized system for the refrigerant loop. BTDT on my way lower volume A8 for example. Whether USA or Canada, it should be the same refrigerant and same techniques and shop equipment.
Basically system is evacuated first. In doing that, they can weigh what came out. Then it is refilled by weight to the right spec. The dealer can do it of course, but then you just pay 2x for it and it is same underlying equipment and refrigerant. USA cost is (rarely) as low as US $ 80-100 (plus maybe refrigerant), and on up to US $150-200 complete. If the weights come back saying it was low, you may want to have them put in uV leak detector dye. Then in turn with any dye stains that show up, now the dealer has an actionable fix item. You can also then discuss what you spent to do the diagnostic they should have done to begin with. If it was correct, then your issue is elsewhere in system. In that regard, your other diagnostic would be a good VCDS scan. Not a quasi worthless OBDII engine only scan tool to be clear, but a good scan tool like VCDS that can reach into the HVAC module and look for codes, whether failed sensors, or fan malfunction, or various system flaps/doors, or whatever. Again, stuff dealer could have done...
AFAIK Audi's just use a high pressure limit switch, as opposed to one reading the pressure level in general. Thus no VCDS help on pulling pressure readings. The switch itself can fail, which cuts out the AC. VCDS would tell you if there is a sensor error or apparent misread. VCDS will also tell you compressor duty cycle; they don't use the old fashioned clutch that clicks.
Audi's do lose refrigerant, but not in two years to point of system malfunction. They shouldn't, but in practice small leaks often go unnoticed and folks skip over until system starts to falter. On the D3 A8's for example that are now 8 to 14 years old, many of us are seeing it lose enough that by 6 or 8 years the system is starting to basically no longer work. The fill weight on those though is very small by old stds. (630g); don't know what it is on Q5. Once it drops by half, system doesn't work, which on that model is then only about 11 oz. by weight.
The simple likely fix is to recharge it. Don't use the can crap since you have no way of knowing what is in there fill wise, or if properly filled back when it was built. If overfilled, you can blow compressor with time, which then costs you 100x the seemed-like-a-good-idea-at-the-time can gig. It sounds like maybe you can't buy it as a consumer in Canada anyway.
Instead, go to an AC repair place. you do not need a dealer for some special "Audi magic" on what underneath is a pretty standardized system for the refrigerant loop. BTDT on my way lower volume A8 for example. Whether USA or Canada, it should be the same refrigerant and same techniques and shop equipment.
Basically system is evacuated first. In doing that, they can weigh what came out. Then it is refilled by weight to the right spec. The dealer can do it of course, but then you just pay 2x for it and it is same underlying equipment and refrigerant. USA cost is (rarely) as low as US $ 80-100 (plus maybe refrigerant), and on up to US $150-200 complete. If the weights come back saying it was low, you may want to have them put in uV leak detector dye. Then in turn with any dye stains that show up, now the dealer has an actionable fix item. You can also then discuss what you spent to do the diagnostic they should have done to begin with. If it was correct, then your issue is elsewhere in system. In that regard, your other diagnostic would be a good VCDS scan. Not a quasi worthless OBDII engine only scan tool to be clear, but a good scan tool like VCDS that can reach into the HVAC module and look for codes, whether failed sensors, or fan malfunction, or various system flaps/doors, or whatever. Again, stuff dealer could have done...
Last edited by MP4.2+6.0; 06-23-2018 at 10:31 AM.
#10
AudiWorld Super User
I'll back up all the way to start. Thus, pressure reading from gauge is doesn't tell you much without adjusting it for ambient temp. The lower the ambient temp, the lower the reading should be. It looks like that gauge face may be twistable in some way to get the blue and red shaded areas to line up. You also would need the Audi pressure specs; a generic gauge face doesn't really tell you that except rules of thumb.
AFAIK Audi's just use a high pressure limit switch, as opposed to one reading the pressure level in general. Thus no VCDS help on pulling pressure readings. The switch itself can fail, which cuts out the AC. VCDS would tell you if there is a sensor error or apparent misread. VCDS will also tell you compressor duty cycle; they don't use the old fashioned clutch that clicks.
Audi's do lose refrigerant, but not in two years to point of system malfunction. They shouldn't, but in practice small leaks often go unnoticed and folks skip over until system starts to falter. On the D3 A8's for example that are now 8 to 14 years old, many of us are seeing it lose enough that by 6 or 8 years the system is starting to basically no longer work. The fill weight on those though is very small by old stds. (630g); don't know what it is on Q5. Once it drops by half, system doesn't work, which on that model is then only about 11 oz. by weight.
The simple likely fix is to recharge it. Don't use the can crap since you have no way of knowing what is in there fill wise, or if properly filled back when it was built. If overfilled, you can blow compressor with time, which then costs you 100x the seemed-like-a-good-idea-at-the-time can gig. It sounds like maybe you can't buy it as a consumer in Canada anyway.
Instead, go to an AC repair place. you do not need a dealer for some special "Audi magic" on what underneath is a pretty standardized system for the refrigerant loop. BTDT on my way lower volume A8 for example. Whether USA or Canada, it should be the same refrigerant and same techniques and shop equipment.
Basically system is evacuated first. In doing that, they can weigh what came out. Then it is refilled by weight to the right spec. The dealer can do it of course, but then you just pay 2x for it and it is same underlying equipment and refrigerant. USA cost is (rarely) as low as US $ 80-100 (plus maybe refrigerant), and on up to US $150-200 complete. If the weights come back saying it was low, you may want to have them put in uV leak detector dye. Then in turn with any dye stains that show up, now the dealer has an actionable fix item. You can also then discuss what you spent to do the diagnostic they should have done to begin with. If it was correct, then your issue is elsewhere in system. In that regard, your other diagnostic would be a good VCDS scan. Not a quasi worthless OBDII engine only scan tool to be clear, but a good scan tool like VCDS that can reach into the HVAC module and look for codes, whether failed sensors, or fan malfunction, or various system flaps/doors, or whatever. Again, stuff dealer could have done...
AFAIK Audi's just use a high pressure limit switch, as opposed to one reading the pressure level in general. Thus no VCDS help on pulling pressure readings. The switch itself can fail, which cuts out the AC. VCDS would tell you if there is a sensor error or apparent misread. VCDS will also tell you compressor duty cycle; they don't use the old fashioned clutch that clicks.
Audi's do lose refrigerant, but not in two years to point of system malfunction. They shouldn't, but in practice small leaks often go unnoticed and folks skip over until system starts to falter. On the D3 A8's for example that are now 8 to 14 years old, many of us are seeing it lose enough that by 6 or 8 years the system is starting to basically no longer work. The fill weight on those though is very small by old stds. (630g); don't know what it is on Q5. Once it drops by half, system doesn't work, which on that model is then only about 11 oz. by weight.
The simple likely fix is to recharge it. Don't use the can crap since you have no way of knowing what is in there fill wise, or if properly filled back when it was built. If overfilled, you can blow compressor with time, which then costs you 100x the seemed-like-a-good-idea-at-the-time can gig. It sounds like maybe you can't buy it as a consumer in Canada anyway.
Instead, go to an AC repair place. you do not need a dealer for some special "Audi magic" on what underneath is a pretty standardized system for the refrigerant loop. BTDT on my way lower volume A8 for example. Whether USA or Canada, it should be the same refrigerant and same techniques and shop equipment.
Basically system is evacuated first. In doing that, they can weigh what came out. Then it is refilled by weight to the right spec. The dealer can do it of course, but then you just pay 2x for it and it is same underlying equipment and refrigerant. USA cost is (rarely) as low as US $ 80-100 (plus maybe refrigerant), and on up to US $150-200 complete. If the weights come back saying it was low, you may want to have them put in uV leak detector dye. Then in turn with any dye stains that show up, now the dealer has an actionable fix item. You can also then discuss what you spent to do the diagnostic they should have done to begin with. If it was correct, then your issue is elsewhere in system. In that regard, your other diagnostic would be a good VCDS scan. Not a quasi worthless OBDII engine only scan tool to be clear, but a good scan tool like VCDS that can reach into the HVAC module and look for codes, whether failed sensors, or fan malfunction, or various system flaps/doors, or whatever. Again, stuff dealer could have done...
The "only" true way to recharge an A/C system is to evacuate and fill by "weight".
The Q5 A/C system Freon load weight is approximately 1.2-1.5 lbs.
There are 6 different A/C systems in the Q5 according to the service manual. Each system will give different static pressure readings at the same ambient temperature. Thus pressure gauge readings are system dependent and won't allow you to add Freon in any meaningful way.
Most A/C Freon leakage loss is at compressor pulley shaft seal. Also remember that excessive loss of Freon is also a loss of compressor/system oil and oil needs to be added to the system accordingly.
My good local A/C shop evacuates the system and recharges for $50 plus any additional Freon cost over what they initially removed. Most total costs are less than $75.
Last edited by Bob Petruska; 06-25-2018 at 05:57 AM.