Audi A3 coolant migration - repeat failure!

[MadUKDiver]

Wife's Audi A3 Sport 1.8 TFSI S tronic, new in March 2013, less than 40,000 miles.

In August last year suffered a coolant leak which was repaired by the local dealer at quite some cost link

And now last week she broke down again, VCDS showed a load of "Cylinder x Injector x - Short to GND" type faults and the dealer diagnosis is "water ingress into the main wiring harness" and a potential repair bill of £1,300

I have to say I'm flabbergasted that this could happen twice so I started searching for other reports of this type.

From their explanation I hadn't realised that the leak is actually through the valve at system pressure into the harness, I had imagined a 'drip' type leak onto some wiring.

Looks like quite a well known issue in the past - example A8 ; VW report including TSB

Last time the dealer inferred that the leak had come from the "Thermostat housing", this time they suggest the "Coolant Shut-Off Valve N82". The latter seems to have been subject to a campaign (on A8) in the USA

Given the prevalence and awareness of these leaks and the general severity and cost of the damage caused it really annoys me that they didn't change all of the high risk items last time - i.e. the 3 typical valves and sensors that could leak into the wiring.

Also with the relatively short time between failures I wonder if last time they actually found the root cause or just treated the symptoms and the coolant may be leaking in from yet another location - e.g. the coolant tank sensor.

Ok, so it's repairable but now the wife has understandably lost confidence in her A3 and so were likely to be buying another motor soon.

I don't see any real solutions on the web, just buy a warranty and push the cost onto someone else.

Anyone any useful thoughts or experience on coolant migration?

[MadUKDiver]

The dealer is now going to repair FOC so ++ Big Thank You Audi !!

And more importantly (for my wife's peace of mind) they are going to check all the other potential know failure points for coolant migration to reduce the likelihood of this happening again.

[FLAPPERJACK76]

Interesting. Never seen it before and IMHO I would definitely consider moving away from this vehicle after the "fix".

Sent from my SM-G930F using Tapatalk

[Scott K]

Good result. Funnily enough, our S3 lost the coolant and my wife topped it up (I was away with work) but the level went down again. Took it in for a warranty repair. Must try and find out what they changed.