No air flow with air conditioner after a few miles

powerfool

Veteran Member
Joined
May 25, 2012
Location
Indianapolis Metro Area
TDI
None anymore
So, I have my 2014 Passat SE... it is a nearly 70k miles now. Last summer we started having an issue with the AC on a trip from Indy to Chicago, and then Chicago to Traverse City, MI, and then back to Indy. Longer drivers, for sure. It would blow cold, and then there was no air flow (everything was still running, including the fan). We let it sit when we got something to eat and we see a huge pool of water (the melted condensation).

We took it in to get serviced and it was low on refrigerant... which makes sense. They tried telling me that it is "normal" to have it low and that some gets "consumed" which is total BS. I told him if that were the case... some politicians would have taken all of our air conditioners by now. Anyhow... it worked fine for a couple of weeks and then started happening again. We took it back assuming they could find the leak this time because of the dye in the filled up refrigerant... and nope.

So, we got into winter time and I wasn't that worried about it because we weren't going to be driving much, but I was concerned about its ability to reduce the moisture when we had defrost on. We didn't have too many issues, though... I imagine that the heat kept it from freezing up and blocking the air flow.

Now that we are back in the warm weather, we took it back. This time... they say that they cannot reproduce it and that the refrigerant is fine. Anyone else have these issues? It isn't even intermittent for me... I can reproduce it pretty much every single time I drive over 10 miles.

Is it possible that the drain for the condensation could be clogged and that is causing an issue? Thanks!
 

unixb0y

Veteran Member
Joined
Oct 1, 2003
Location
Manitoba, Canada
TDI
2013 Passat Comfortline 6MT Nav
So, I have my 2014 Passat SE... it is a nearly 70k miles now. Last summer we started having an issue with the AC on a trip from Indy to Chicago, and then Chicago to Traverse City, MI, and then back to Indy. Longer drivers, for sure. It would blow cold, and then there was no air flow (everything was still running, including the fan). We let it sit when we got something to eat and we see a huge pool of water (the melted condensation).
We took it in to get serviced and it was low on refrigerant... which makes sense. They tried telling me that it is "normal" to have it low and that some gets "consumed" which is total BS. I told him if that were the case... some politicians would have taken all of our air conditioners by now. Anyhow... it worked fine for a couple of weeks and then started happening again. We took it back assuming they could find the leak this time because of the dye in the filled up refrigerant... and nope.
So, we got into winter time and I wasn't that worried about it because we weren't going to be driving much, but I was concerned about its ability to reduce the moisture when we had defrost on. We didn't have too many issues, though... I imagine that the heat kept it from freezing up and blocking the air flow.
Now that we are back in the warm weather, we took it back. This time... they say that they cannot reproduce it and that the refrigerant is fine. Anyone else have these issues? It isn't even intermittent for me... I can reproduce it pretty much every single time I drive over 10 miles.
Is it possible that the drain for the condensation could be clogged and that is causing an issue? Thanks!
I wondering if the AC Coil is icing up. Maybe because of lack of airflow. When was the cabin air filter last changed?
 

ZippyNH

Veteran Member
Joined
Apr 22, 2015
Location
Southern NH
TDI
2015 JETTA TDI SE
Sounds like the drain is clogged...
You need to open it up...
If the coil is submerged, it gonna freeze...and stink.
 

tadawson

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Joined
Jun 14, 2013
Location
Lewisville, TX
TDI
2013 Passat TDI SEL, 2015 Passat TDI SEL
Yeah... that was my thought as of today.
But he says he sees a big puddle (didn't say where, though . . ) when it thaws. This is likelyy classic leak/undercharge, and I suspect that the dealer just blew him off the last time in, since with the newer systems, about the only way to verify charge is to recover/weigh/recharge . . . Pressures just won't cut it any more . . . nor will dyes in the charge, since you can't see everywhere. This needs to be tested with an electronic sniffer - those can detect leak rates under 1 oz per *year*!
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
You should be able to view the evaporator temperature in VCDS.

On the Climatronic system, it will regulate compressor load to prevent the evaporator from freezing. I don't know how the Climatic (manual) climate control system functions.
 

tadawson

Veteran Member
Joined
Jun 14, 2013
Location
Lewisville, TX
TDI
2013 Passat TDI SEL, 2015 Passat TDI SEL
Evap temp isn't the issue - it's glide. The temp on an evaporator is fairly even with a proper charge, but with low charge, all evaporation (cooling) occurs in a small area near the inlet, which promptly freezes, allowing liquid refrigerant to travel farther into the evap, progessively freezing across is. Since the probe only reads one spot, no telling what you will see . . . Likely they would tend to read the outlet side, to ensure adequate refrigerant to cool the entire evap uniformly. If low, outlet likely stays warm, causing the compressor to run at max, and progressively freezing the rest (pretty much the same as a TXV, just controlling flow via the compressor, and not just a valve . . .).
 

thundershorts

Top Post Dawg
Joined
Jul 15, 2010
Location
west chester pa
TDI
2015 passat tdi sel premium 2015 golf s tdi gls tdi b5.5, 2002 eurovan,Peugeot 505 td,Citroen cx25 prestige
If the outside humidity is high, and you are not running it in recirc mpde, the coils in the evaporator will freeze over with ice. if you turn off a/c for a few minutes it will thaw and airflow will be normal. to avoid this just run it in max which is recirc air only
 

tadawson

Veteran Member
Joined
Jun 14, 2013
Location
Lewisville, TX
TDI
2013 Passat TDI SEL, 2015 Passat TDI SEL
In 40+ years of AC use and work in multiple climates, I have *NEVER* found thst to be true with a properly working system! NEVER!
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
Today, I learned...

Evap temp isn't the issue - it's glide. The temp on an evaporator is fairly even with a proper charge, but with low charge, all evaporation (cooling) occurs in a small area near the inlet, which promptly freezes, allowing liquid refrigerant to travel farther into the evap, progessively freezing across is. Since the probe only reads one spot, no telling what you will see . . . Likely they would tend to read the outlet side, to ensure adequate refrigerant to cool the entire evap uniformly. If low, outlet likely stays warm, causing the compressor to run at max, and progressively freezing the rest (pretty much the same as a TXV, just controlling flow via the compressor, and not just a valve . . .).
Thanks, Tim!
 

thundershorts

Top Post Dawg
Joined
Jul 15, 2010
Location
west chester pa
TDI
2015 passat tdi sel premium 2015 golf s tdi gls tdi b5.5, 2002 eurovan,Peugeot 505 td,Citroen cx25 prestige
As I said, turning off the ac for a couple minutes will thaw the ice blocking airflow if the evap coil is iced. Systems are most often designed bleeding hot air from the heater core in to eliminate this. I've seen this many times over the last 60 years and it usually only happens when humidity is very high. You can not recreate this in a shop situation, only in a driving situation. Just set it to max which cuts off most of the moist incoming outside air and it won't happen.
 

powerfool

Veteran Member
Joined
May 25, 2012
Location
Indianapolis Metro Area
TDI
None anymore
What is the latest hardware for VCDS? Is there any iOS equivalent that I could load with a bluetooth device to monitor?

UPDATE: I see the Hex-Net device and VCDS-Mobile. I am actually surprised by the lack of a price different between the Professional and Enthusiast models of the Hex-Net... it is not very significant from a percentage perspective.

As an update, they said that my refrigerant was fine and they couldn't reproduce the issue... but, when I got it back yesterday, it was blowing really cold air. I don't buy it. The guy that mans the phone and scheduling at the service center for my dealer likes to blow a lot of smoke... I don't think I have had a single conversation with him that didn't include a fair amount of BS on his part. If/when this surfaces again, I will take it to another VW dealership (I have one closer to where I live now, anyhow).

On a side note, I had the fix done and the only thing I really notice is regen happening much more often.
 
Last edited:

Rico567

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Joined
Jun 13, 2003
Location
Central IL
TDI
2013 Passat TDI SEL Premium (Turned in 7/7/18)
What is the latest hardware for VCDS? Is there any iOS equivalent that I could load with a bluetooth device to monitor?

<snip>
The latest hardware that incorporates VCDS is apparently the new HEX-V2 model, which I know nothing about, since I bought VCDS-Mobile before it came out. I bought VCDS-Mobile used, and it provides the full features of VCDS (as long as one has access to a wireless network while using it). I bought it, not because I use many of the more sophisticated features, but because most of the rest of the diagnostic units out there aren't very useful.
 

powerfool

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Joined
May 25, 2012
Location
Indianapolis Metro Area
TDI
None anymore
Well, it has started again. This dealer's service department is just the worst. They said everything was fine with the AC when we brought it in and that they didn't have to do anything to it at all. Well, I could tell that was a lie... they had to have topped it off because it was running like new when we got in the car. The wife started her new job that is 30 miles away and it freezes up about 15-20 miles out. I am going to see if I can get at the drain hose myself this weekend. If that isn't it, I am going to take it to another dealer for service.
 
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