UK-POLOS.NET - THE VW Polo Forum

Our Polo GTI+ leaves a wet mark on the drive (driver's side towards the front of the engine). It seems to be clear, so it doesn't appear to be coolant (which is not going down).

The car has manual air conditioning and the puddle is there even when the air conditioning has not been switched on, so I'm sure it isn't the usual air con puddle (I'm assuming that the air con is only on if the yellow led is lit).

Anyone have the same? Any ideas what it could be? Can the air con be on with the yellow led unlit?

Thanks.

well if you drive a car and then switch off aircon and park, there will be water under the car, but if it's off and there is still puddle under a car then somethings wrong.
Maybe stupid to say, but could be if you live in UK that water is on top of the plastic that covers engine underneath the car?
If its not coolant or aircon, oil there is nothing else that could leak.

Could you carefully smell, feel or taste the fluid? Is it water? If so, not to worry. If it feels greasy in any way... not so good. And don't taste it.

If it smells sweet it's coolant. How is your coolant level in the expansion tank?

It probably is aircon condensate. If you look at the "convenience consumers" menu you'll see that the aircon is always on to a small extent, even when you haven't switched it on, especially when the venting is switched tk blowing at the windscreen.

^^Thanks for the replies. The wet patch is definitely not greasy and has no smell. I'm pretty sure it's just water. Also, when the car is restarted, the inside of the screen mists up for a moment before the fan clears it, just as if the air con has been on when the car was last used.

What I don't understand is, we trebble check that the air con is off when we get in the car, i.e. no lit yellow led, even when the air is directed to the windcreen. When the air is directed up to the screen from another position the led comes on automatically, but we immediately switch it off.

I think it must be something to do with the air con, I just don't understand why when it's clearly switched off. It looks like it will just remain a mystery. Actually, the more I think about, I'm pretty sure our old MK7 Golf R LIne with manual air con did the same.

TurboTrev wrote: Sat Sep 12, 2020 9:17 am ^^Thanks for the replies. The wet patch is definitely not greasy and has no smell. I'm pretty sure it's just water. Also, when the car is restarted, the inside of the screen mists up for a moment before the fan clears it, just as if the air con has been on when the car was last used.

What I don't understand is, we trebble check that the air con is off when we get in the car, i.e. no lit yellow led, even when the air is directed to the windcreen. When the air is directed up to the screen from another position the led comes on automatically, but we immediately switch it off.

I think it must be something to do with the air con, I just don't understand why when it's clearly switched off. It looks like it will just remain a mystery. Actually, the more I think about, I'm pretty sure our old MK7 Golf R LIne with manual air con did the same.

You switch the aircon off but it is always on to a small extent, as I explained above, even when the light isn't on. Turn all your aircon off and look at the convenience consumers menu - it will still show use of aircon. somewhere in the region of 1/16 of a gallon of fuel an hour when venting the windscreen without the aircon lights illuminated. It will be considerably more if you purposefully switch the aircon on. No mystery.

Another way see if it could be the air conditioning is next time you go out in the car is turn off the fan for blowing air into the car and see if it leaves a puddle then.

Right, with the help of the monkeyhanger and Google I now understand the CC Menu. We spend most of the time with the airflow 100% on the screen and by using the CC Menu I can see that swiching the air con off makes not a jot of difference. All it's doing is switching the yellow led off, the air con actually remains fully on.

As soon as the airflow is moved off being 100% on the screen, the useage plummets (although it does remain on slightly as mh pointed out). The only time air con useage is nil is if the fan is completely off.

Matter resolved. Thanks for your help.

I'm so confused by this thread....
Manual aircon mentioned, but then climate control mentioned...
Switching the air con button off, but it's actually staying on....
The aircon part of the system should absolutely go off when switched off, I think the OP is confusing the 'power usage' display with the fan being used.

Andy Beats wrote: Mon Sep 14, 2020 9:11 am I'm so confused by this thread....
Manual aircon mentioned, but then climate control mentioned...
Switching the air con button off, but it's actually staying on....
The aircon part of the system should absolutely go off when switched off, I think the OP is confusing the 'power usage' display with the fan being used.

The aircon stays on in the background to a lesser extent than purposefully putting it on, on to a much greater degree when blowing at the windscreen than venting to the occupants. The convenience consumers menu on the MMI clearly shows this.

All European spec. Polo(AW) have the compressor stays on in the background when blowing at the windscreen, even the LED light on the A/C button is OFF.

Because in the 08-Auto HVAC control module, the coding is set to "Operating restriction in defrost mode, Standard".

If you use VCDS and change this coding to "Operating restriction in defrost mode, Unrestricted", you will have full manual control of the aircon.
By mean when blowing at the windscreen, when the LED light on the A/C button is OFF, the compressor is really switched off.
And the compressor is switched on, when the LED light on the A/C button is ON.

To do this, using VCDS:
- Go to Coding of 08-Auto HVAC
- Go to Byte 11
- Change bit 2-3 to "Operating restriction in defrost mode, Unrestricted"

^^That interesting and good to know. Thanks for posting.

Best to leave the aircon as is. If you have it off completely for long periods then the seals keeping the refrigerant gas in place will dry out and leak it all out. You'll need a regas every 2 years. What it's using is a tiny amount unless you are perpetually in gridlock. Plenty of people throw pounds away chasing pennies.

monkeyhanger wrote: Mon Sep 14, 2020 8:34 pm Best to leave the aircon as is. If you have it off completely for long periods then the seals keeping the refrigerant gas in place will dry out and leak it all out. You'll need a regas every 2 years. What it's using is a tiny amount unless you are perpetually in gridlock. Plenty of people throw pounds away chasing pennies.

If you change the coding of 08-Auto HVAC to "Operating restriction in defrost mode, Unrestricted", it doesn't mean your compressor is permanently OFF forever.
By changing the coding, it give the user the freedom to choose switching ON/OFF the compressor in any mode of air blowing.
So, nothing is stopping the user switching ON the compressor from time to time, in order to lubricate the seals / the compressor.

I heard many people say it is better to keep the compressor ON all the time, so it can lubricate itself and the seal... etc.

From my practical experience, I had a 2007 Hyundai Getz 1.4 and I only switch ON the compressor once every 1 - 2 months, when I sold the car it is 12 years old with 220 000km on the clock, the aircon is still ice cold, still using the original compressor, never regas or replaced anything on the aircon system. Same thing goes to my 2009 Daihatsu Sirion 1.3, when I sold this car it is 10 years old with 100 000km.

On the other hand, I know many VW owner in Hong Kong, a hot climate area where they have their compressor ON all the time. Every single one of these VW owner in HK experience aircon regas and compressor replacement during their ownership of their VW within 10 years.

So, I don't know anymore what is the correct way to protect the aircon system???
Run the compressor all the time??? Or, only run the compressor for about 10-15min. once or twice every month???

ho8882000 wrote: Mon Sep 14, 2020 8:05 pm All European spec. Polo(AW) have the compressor stays on in the background when blowing at the windscreen, even the LED light on the A/C button is OFF.

That makes more sense, the impression I was getting was others were saying it stayed on in the background under any setting - which didn't ring true.