Really bad smell when first turn on AC

[Hillbilly]

Its in D48806031A9 Heating- Airconditioner Page 132/133


Workshop manuals for MKII TIguan

[grimmdex]

I had something similar with my car, I very strong and offensive chemical smell when I turned on the aircon. It took a while to work out where it was coming from but when I pulled out the pollen filter it was the same smell. It also smelled similar to the washer / wiper fluid that was in the car when I bought it which did not smell nice. Whoever filled up the wiper fluid tank must have used up the whole bottle. I drained and replaced the wiper fluid and also changed the pollen filter to an Aussie foam brand and its all fixed.
I'm wondering is it possible for water from the windscreen washing to somehow end up soaking in the pollen filter?

[noobatron]

I had the exact same problem with my 2015 BMW X1. The problem ended up being a blocked condensation drainage hose that caused water to build and eventually soak the polled filters causing them to go mouldy and hence that smell you get.

Turn your AC on and run in for about 10 mins. Check to see if there's water from the AC condensation drainage hose. If you don't see any water then chances are, that hose may be blocked or something's preventing the water draining way from the AC unit.

Thanks to Hillbilly for the workshop manual. As Hillbilly said, check out D48806031A9 Heating- Airconditioner.
I found the section for the condensation drain on page 160.

[REXman]

Sorry to revive the thread but I changed my pollen filter and it made no difference. I did it myself and while I was there I checked out the existing filter - no smell or issue with it at all. They seem pretty good quality from factory you could just give it a few smacks in the ground and reuse.

[notaGolfR]

Try drying out the system by having the a/c off with temperature and fan dialled to max & running in re-circulate then fresh. Do for all vents and modes. That might kill mould and turn it to powder. Remove & clean the filter again then replace and see how you go. If getting desparate you could try introducing some Glen20 which is mainly ethanol at the fresh intake then use lowest fan in all modes then repeat at full fan. Even blowing air back thru the system might dislodge e.g. a rodent but check with the manual if that can damage e.g. valves/flaps.
After using a/c (if I remember) I turn it off, raise the temp & blast at hight fan to dry out.

[iDiesel]

Issue was fixed during last service they replaced the pollen filter
Working fine again - especially after these last few days, woah it’s been hot!!!

[FastMitch]

I had the exact same problem with my 2015 BMW X1. The problem ended up being a blocked condensation drainage hose that caused water to build and eventually soak the polled filters causing them to go mouldy and hence that smell you get.

Common trick from Dealers to generate 'work' is to block the condensation drainage hose during a service job

Once they block the hose, the whole system fills with moisture and stays there when the engine is turned off

This creates mold and bacteria that then causes a rank smell that infects the whole AC system

Clearing the drain hose may require some hot days to dry out the system before the smell disapates as well as replacing the cabin filter

Last SUV dealer wanted to charge me a 'flush and cleaning fee' where they would put a 'cleaning' gas through the system. Cost $200

[Ozsko]

Common trick from Dealers to generate 'work' is to block the condensation drainage hose during a service job

That sounds like an urban myth to me. I have had decades of involvement at dealer level and have never seen this done.