AC evaporator cleaning question

[2226]

I have previously done the AC bomb thing in my 2017 6C. Just set off a can of disinfectant and shut the doors and let the AC run.

I have a can of Wurth evaporator disinfectant/cleaner.
This comes with a long hose to be inserted in the AC drain hose to get to the evaporator.

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The 6C doesn't have a regular drain hose as such, just a exit port behind the firewall padding.
Has anyone done evap clean using that port? Shouldn't be a problem, should it?

PS: I'm basically bored ... tomorrow is a public holiday ... I have all these chemicals in the garage and I am gonna bl**dy use them.

[RUM4MO]

A very long time ago, that was the way that car evaporators were sanitised - and I might just have a tin of "stuff" that has that same long straw - but I've got no plans to use it - if I can ever find where I stored it, the long straw is kept in beside a central heating boiler, so that it is flexible - I think that was the plan many years ago!

So, I tend to use bombs, but first of all I remove the pollen filter as there is not much point in letting it capture lots of the stuff that is meant to be passed round and round the car's cabin air system, ie after running a bomb thro the AC system, I fit a new pollen filter.

I'm not sure that that stuff was meant to get blasted into the water drain, I thought that the instructions requested that it went in somewhere else so that it got passed through the cabin air plenum box including thro the evaporator. There must be an "air return" path that takes cabin air back into the plenum when the recirc flap is set correctly. Maybe investigate using a piece of light cloth to see where the air gets sucked in, and stick the end of the straw in that air path.

[2226]

I've seen them feed it into the air ducts as well.
The instructions on Wurth's site say to feed it into the drain pipe.

There are foam type cleaners that are used in the same way. Those seem to be more effective due to dwell time on the evaporator. Actually, Wurth have one like this, but I can source locally.

I have run a bomb through it before, but that wasn't as effective as I thought it would be. Was hoping to get a more direct shot on the evaporator where most of the mess is.

[RUM4MO]

Oh well, stuffed up the drain it is then, maybe I should try to find my one and use it!

[2226]

LiquiMoly have one of these as well.
Same application instruction.

But looking at the spec the LM has a pH of 7.0 and this Wurth is 5.0. Not sure if that's gonna be a problem being slightly acidic.

I just did a search for how to access the evaporator and wound up watching a removal procedure.
Oh damn, whole dashboard out.

Been hearing of a number of evap replacements happening around here as the 6C ages. Seems there's an issue with them leaking.
Don't have that issue thankfully.

[RUM4MO]

Hum, on the subject of leaking evaporator, I have a feeling that that is what is wrong with my wife's August 2015 Polo 1.2TSI, I can't find the leak, it is sealed well enough to be legal for a car AC place to recharge, but the charge only lasts 4 weeks, or now maybe even less, which is good enough to span "peak summer heat" in Scotland - so far!

I suppose the plan nowadays is to keep as close to neutral ph as possible with everything.

[2226]

From what I can see online, the leak is along the weld on the evaporator. I guess heat cycling will eventually get it.

I haven't topped up charge on mine since I bought it in 2019 and the AC still works. Probably can do with a recharge as it's not as cold as I remember.
I just want to get rid of some of the funk when I do use it.

I miss the R12 from my '89 Audi. It was amazingly cold, but eventually formed a leak on one of the schraeder valves and I never sorted that out.

You probably have a leak somewhere, but not necessarily the evaporator. The low- and high-side valves tend to be the culprits on AC. Worth getting some dye into the system and then check for a leak. My mk1 Golf has AC and it took a stone to the condensor. The dye covered everything. Quite a funky thing under a UV light.

[RUM4MO]

I've had a leaking pressure transducer on a 2009 SEAT Ibiza - same as VW Polo, that was easy to spot and fix with a genuine latest version of transducer from VW Group.

Dye, yes, it will probably come to that, my only issue with that is, and agreed with with a proper large fridge plant engineer, using dye is aimed at quickly finding and fixing the only leak that a system has, when the dye escapes it tends to cover a large area, and so looking for traces of dye will not work the next time unless a serious bit of cleaning has been done after the first dye application.

I've got a R143A pumped sniffer - but completely failed to locate any leak(s).

I really do need to get the front of that car out into the service position and get the condenser out for a good look at it.