18000 miles till first service is just wrong , the life of the engine and other componants must be shortened considerably
im no vw mechanic but im pretty sure there is no sensor that tests for oil quality and condition the ecu uses time and mileage to decide when a service is due
if my new car had 11000 miles on it it would have had at very least an oil change 5000 miles ago
From VW’s website;
do you believe all the marketing sh!te ?
This Flexible regime has been made possible due to the development of new Volkswagen engines with the latest technically advanced longlife oil. These engines use built-in sensors that continually monitor the oil quality, making it possible to enjoy reliable and confident motoring for up to a maximum of 18,000* miles or 24 months (whichever occurs first).
https://www.volkswagen.co.uk/owners/servicing/service-plans/regimes
The only sensor I'd imagine could be in there to directly monitor oil quality would be a conductivity sensor monitoring the conductivity of the oil (more metal in the oil increases conductivity, presumably - I don't know for sure whether clean oil is a good electrical insulator).
More likely there's a set of algorithms that decide when to call time on your oil due to how long/fast/hard.you've been driving your car between services e.g. lots of cold start short journeys are going to shorten the interval vs Mr Motorway Mile Muncher doing 30+ miles per journey.
Modern fully synthetic oils are fine going to 20k miles as long as your filter is effective in removing particulates attributed to engine wear, their stability under operating conditions over extended intervals is fine.
My only issue with high mileage service intervals is for TDI engines with plenty of interrupted active regens - induced regens through injecting fuel into the exhaust system to raise DPF temps. If you interrupt tgat cycle by ending your journey, that fuel ends up in the sump, diluting your oil. Hopefully the car would have algorithms to know that is happening or knows through reduced oil pump work that viscosity of fuel is reduced.