Bought a 2020 GTI+, mooing brakes and whiteworm brescias

[Noosh]

Hello all,

I got a massive car upgrade last week coming from a 2013 Swift Sport to a 2020 Polo GTI+. I took a while to familiarise myself with the GTI and GTI+ trim and found one to my liking that I bought after a test drive last week.

Having read the forum, I knew of the whiteworm issue of the Brescia diamond cut alloys and did see it before buying the car that all the wheels are affected in one shape or another.
I've not brought the car to a garage as of yet, but wondering what would be the most economical way of fixing it. I need to take some pics but I think it's pretty visible on one wheel especially, 2 are somewhere in the middle and one where it's just starting I think.

Having bought the car last week, I only got the mooing brakes this morning when reversing out of my car spot, and it was SUPER loud. Considering it was raining but my car is in a covered carspot it was damp at best and hadn't been driven for only 24 hours.

I read that there were VW parts that were made to fix the issue, clearly the previous owner did not get it fixed and now that the car is out of warranty, does anyone know how much VW will charge to fix? I guess I need to see how often it appears, but having read about it on the forum, I immediately knew what it was.

A few other questions I have whether that's normal, or a bad sign.
- I can clearly hear the rear camera going back into its spot, but it's semi loud, wondering if that could be a sign of a soon to die rear camera motor.
- The car has Michelin 225/40/18s Pilot Sport 5 on, which are also fairly new (5.5mm of tread left overall), so I really don't want to change them. However, I read there might be some slight modifications to do to make sure it doesn't rub to the wheel arch, I doubt that was done, and has probably done a few thousand miles with those on already.

Haven't really done more than one 30 miles A-road trip when I picked it up and small town trips to work and other errands so far, but will find out how it behaves on longer trips this weekend

Although I'm seeing higher fuel consumption than expected - being european I switched to L/100km in the unit display so bear with me - but seeing north of 12L/100km which online calculators lead me to believe that's 20-25mph on short trips, is that to be expected? (Really short trips within town of 10-15mins in 20 and 30mph zones). As mentioned I can see how much I use from Cambridge to Sussex next weekend.

I did use 11 or 12L/100km when I got the car on a 45 minute drive but... since I just got it I was obviously not driving smoothly!

Thanks! Noosh

[SRGTD]

Welcome to the forum @Noosh.

The clear lacquer on bare metal finish on diamond cut alloys isn’t very durable, and it’s not unusual for white worm corrosion to start when the alloys are between 2 - 3 years old (sometimes sooner), especially if the alloys are on the car throughout the winter months. The only real way to rectify the white worm issue is a full refurbishment of the alloys, and the cost of a high quality professional refurb (acid strip, prime, paint/powder coat, re-cut the face of the wheel, apply protective lacquer, oven bake) is likely to be in the region of £130 - £150 per alloy. Even after a professional refurb, white worm may return after another 2-3 years - especially if there’s any stone chip damage to the lacquered surface that’s left unrepaired. I personally dislike diamond cut alloys with a passion!

The mooing rear brakes; mine do this but usually only after I’ve washed the car. I get the mooing noise during first use of the brakes after washing - when reversing out of my garage and up my driveway to the road; after that, they’re silent in operation. The mooing noise doesn’t affect braking efficiency.

Reversing camera was an extra cost option so there may not be many GTI / GTI+ owners on the forum with a reversing camera. I do have one, and yes, I do hear the motor camera retracting the camera back behind the VW badge / hatch handle after reversing, and what you’re describing I’ve always considered to be normal. I’ve owned my car for nearly 4 years and it’s always made the noise, so I don’t think it’s a bad sign of imminent failure of the motor.

Factory spec tyres for 18” alloys on the GTI / GTI+ are 215/40 R18 but because 225/40 R18 tyres are significantly cheaper, some owners have fitted these. From memory, one or two previous forum members had an issue with the inner face of the rear tyres rubbing the fabric wheel arch liner, but that was because the wheel arch liners hadn’t been fitted correctly when the car was built. If rubbing is experienced, it should be possible to loosen off the screws holding the rear wheel arch liners in place, reposition the liners (they are quite flexible) and re-tighten the screws.

Fuel consumption - my long term average is 43 - 44 mpg (I have had upper 50’s mpg on some journeys). On short, urban journeys in town I usually get 33 - 35 mpg. I’m not a typical GTI driver; retired, and I rarely drive enthusiastically and usually just go with the flow of the traffic. If you’re doing a high proportion of short journeys on a cold engine, then poor fuel consumption may be an indication of your car’s GPF (petrol particulate filter) going through a forced regeneration when additional fuel is used to help neutralise particulate matter that’s accumulated in the filter. Check out the discussion topics at the links below;

https://www.uk-polos.net/viewtopic.php?t=79327

https://www.uk-polos.net/viewtopic.php?t=73177

[Noosh]

Thanks for the thorough answer.

For fuel consumption, I read about the GPF before buying the car, and I don't think so as my auto-start is definitely working (and I don't know why I haven't disabled it yet as it's extremely annoying in town when it stops even though you want to go one second later...).

I guess I will likely live with the whiteworm until it gets bad enough to warrant a refurbishment...

I'm assuming the mooing brakes will be fairly frequent with my car as my car is left outdoors but with a little roof over it, it still gets damp it seems.