Air conditioner not cooling intermittently...

...while slowly crawling in traffic on the A6 4F, the air conditioning turned off (outside temperature was approximately 28°C), but it started working again after driving for 8km.

With this, the water level and the compressor can be ruled out as potential sources of error. Does anyone have a quick tip?
I'll connect VCDS this afternoon; hopefully, it will reveal the cause of the shutdown or indicate if there's an error code registered (link: /viewtopic.php?t=3475).

Best regards, Rainer.

Hi Rainer,

When stuck in traffic, the temperature of the condenser becomes a concern. A plausible scenario would be non-functioning radiator fans or a clogged radiator core.

But of course, there are still many other possible causes, such as faulty temperature sensors or defective high-pressure sensors.

Regarding the fill level: If there is too little refrigerant, the evaporator would be less full. This would result in a significantly higher temperature difference across the evaporator (with a higher average temperature), but also a lower evaporation temperature at the inlet (due to less refrigerant mass, less pressure, and less temperature). If the evaporation temperature sensor is located there, it could also trigger a shutdown due to localized evaporator icing. Therefore, I would not completely rule out a refrigerant shortage as the cause of this problem. However, I don't understand how the absence of this effect relates to the situation (the relationship between higher rotational speed and higher mass flow is not as direct in controlled swashplate compressors).

Let's participate in the cause.

Greetings.
Guste.

100% sure that the air conditioning was turned off? Or could it also have been that warm air from the heating system was involved? The latter often happens with the 4F, due to faulty heating valves.

Hello,

"I've already experienced defective electric fans in both the Passat 3B and the A2 models within my own fleet of vehicles – so it could be a potential issue." I managed to get the A2 working again by disassembling it and manually moving the carbon brushes.

Bye.
peace

The cold air flap (V197) has a mechanical fault (error code 00018 - servo motor for cold air flap V197).

Let's see which valve this is, where it's located, and whether we can damage anything by performing an actuator test.

Best regards, Rainer.

It's also a good idea to check if all the cooling fins on the capacitor are still present, as they sometimes detach. Most recently seen on a vehicle... there, about 40% had crumbled away due to heavy condensation.

Thank you for the information! Just checked: Fortunately, it looks relatively free of rust.

Is the electric fan on the right side still working? Often, the control unit for the fan is faulty. The viscous fan on the left side is often not powerful enough to cool the condenser. The error usually only occurs in the MSTG.

Hello T3Surfer,

There is no viscous fan operating, but both electric fans are running.

I've now had the various actuators of the air conditioning system "work" a bit and am waiting to see if the error reappears. If necessary, the cost of a new V197 should be manageable, but the effort required to install it is questionable.

Best regards, Rainer.

dieselschrauber wrote:

If necessary, the cost of a new V197 should be manageable; the only question is the effort required for its installation.

That's how it is.
Therefore, my plan for the WRC Polo is: As soon as, for the first time (after the warranty expires), a valve motor fails, the entire climate control system will be converted to a manual version .
It will be a bit more expensive than just replacing the flapper motor, but looking back, converting to manual at the first opportunity would be the better option, especially considering that the flapper motor will need to be replaced at least three times. It would have been cheaper to replace it.

"Manually" doesn't work any better than "automatically and broken"...
Here's the translation:

"With the old locomotives of my youth, everything was manual, yet problems still arose with the heating control system, such as stuck valves and broken levers. What's the benefit/point of converting to a manual system in that case?"
Whether I'm driving around with the heater on in the car at an outside temperature of 30°C because the adjustment lever is broken or because a servo motor is defective, it doesn't make any difference.

You can find a V197 for under 20 EUR.

[Translating...]

...it's a state of mind...

dieselschrauber wrote:

Whether I'm driving around with the heater on in the car at an outside temperature of 30°C because the adjustment lever is broken or a servo motor is defective, it doesn't really make a difference.

The result is the same.
But I've already read hundreds or even thousands of frustrated posts online about spinning servo motors (or their encoders), while you're the first writer I've encountered who deals with manual AC systems.
Since I don't believe that manual ACs account for only 1% or less of the market compared to Climatronics, my assumption that manual ACs have higher reliability remains .

Hi,

Quote:

I've now had the various actuators of the air conditioning system "work" a bit and I'm waiting to see if the error reappears.

"So far, it has worked great on the Polo - along with a little WD40 sprayed into the potentiometer. Interestingly, the engines threw errors quickly during a diagnostic test while the car was running. What really helped was the learning function. I ran it approximately twenty times in a row (it goes all the way to the limits), and after that, everything was fine." With VCDS, it was also possible to clearly see how the values at the connection points became more stable with each run.

Quote:

If necessary, the cost of a new V197 should be manageable, but the effort required for its installation is questionable.

Here's where creativity comes in... For example, for the 9N, there are guides available in relevant forums that require significantly less work than the official ones.

Overall: Before I would convert the entire system to manual operation, I would simply design and install more robust position sensors. There is enough space around the motors and flaps in both the 9N and the 1Z to accommodate an external construction. Ultimately, it only needs to convert a rotation or a position into a voltage – there are more than enough solutions that are more durable than such a cheap potentiometer on the rotating axis. It probably wouldn't even matter much if the relationship between rotation and voltage is not 100% linear (which would happen with a position sensor instead of a rotary encoder). If you do it skillfully, it can even be done without a complete overhaul, because it's easier to access the moving parts than to remove the entire motors.

Best regards,

Jan.

You are worried...

Yes: These actuators occasionally fail. Yes, VW produces hundreds of thousands of cars, so it's not surprising that you can find many articles online about unusual servo motors.

Here are the VAG vehicles with Climatronic that I have in my immediate surroundings:

My Passat, manufactured in 2008, now has approximately 230,000 kilometers on the odometer. You can occasionally hear the engines idling, but everything is still running smoothly. No actuator motor has been replaced yet.

Our Galaxy MJ 2005 (which is a Sharan) still has the original stepper motors at approximately 190,000 km.

My father's A8 MJ2000, which has Climatronic and approximately 340,000 km on the odometer, still has the original engines.

My brother's Passat 3C, manufactured in MJ2007 (and likely with 100,000-150,000 km on the odometer), still has one of the early engine versions.

My sister-in-law's Golf Plus is now, at the end of its automotive life, also experiencing issues with its engines.

I don't have any more VAG vehicles in my immediate surroundings.

Either the problem isn't as extreme as it seems, or you should consider marrying into my family to be protected .

Perhaps the servo motors have improved over the years .

On my 1996 A6 C4, I've "reactivated" those things a total of 3 times. In a way, he still had the first ones until he sold it for 19 [units/dollars/etc.].
Actuator diagnosis or adaptation would not have helped in this case; instead, wear debris from the motor brushes had accumulated in the motor's collector, creating a short circuit that bypassed the normal current flow. They got a little warm, but they didn't move anymore.

I would, of course, be happy if, despite all the "optimizations," these things lasted longer than 10 years.

Regards,
olli