Well, he does have a warranty, and barking up the corporate tree often does get results.
The only way VW comes up with the tech bulletins for common problems and their solutions, along with production changes and improved parts for problems is if dealers cooperate and send their feedback about every issue they encounter with new cars. Dealers can be a pain to deal with, but speaking as someone who's worked for a dealer, the manufacturer very much does want dealer cooperation to catch any and every common issue so they can quickly make necessary changes/improvements on any new model car. They do a number of things to encourage/incentivize dealer feedback on vehicle issues, and they have corporate technicians available for every region who can step in and look at cars themselves to give more detailed feedback to corporate if needed. But, it all hinges on how good the individual dealer (and in many cases, individual technicians) is at utilizing that system and for owners to bring their cars in.
Now, that might be a little different with these leftover TDIs, though, since they aren't producing them anymore and we might not get any new production models with the same engines the 2015s came with... So, it is a bit of an orphan.
Getting things warrantied at the dealer level can be a struggle at times, but not a totally futile one if you play it right. And it's necessary to the development of new cars themselves as well as fixes to the still under warranty vehicles to have customers come to the dealer and have the dealer provide feedback to VW. If those things don't happen and everyone basically says "screw the dealer, don't go to them" VW doesn't get made aware of common issues as easily and thus doesn't come up with fixes to what might be common problems.
VW has had a number of common issues crop up on recent cars, and some parts have gone through numerous revisions in the process of trying to find a long-lived fix. And every part that gets warrantied gets sent back to VW for evaluation. They will disassemble it for evaluation, and in the case of their frequently leaky TSI water pumps, they've even looked at residues found on gaskets and noted some of the repeat failures had oil on them, leading to gasket failure. So, they recommend finding and fixing any oil leaks to go along with replacing the water pump, and they've also reformulated the gasket material to be more oil resistant along with changing the formulation of the plastics and even changing one section of the assembly to metal on the most recent revisions.
They've had several revisions of the commonrail high pressure fuel pumps. Pre 2013 models have an extended warranty to 120k miles (at least in California, that's the duration of the extended warranty, some states it might be as low as 80k).
They've had revisions of the TSI intake manifolds for a failure of the intake manifold runner flap system that causes them to not be able to move through their full range of movement, thus setting a DTC for IMRC control difference. They've offered an extended warranty for 120k miles for this issue.
They've had a recall for late Mk5s and Tiguans (maybe expanded to other models now) where a 30A fuse for the body control module likes to get a little melty, and then you suddenly find yourself with half your exterior lights not working, and it might change every time you key it on as to which lights aren't functioning. An updated, more heat-resistant fuse and new fuse panel fixes that under an extended warranty.
These are just a handful of the things I was doing a couple years ago at the dealer. None of these fixes would have an extended warranty or updated parts if it weren't for feedback provided to the dealer and the dealer getting VW involved and sending the old parts back for evaluation.
It's a very large, complex system, and sometimes you get bad individuals at the dealer level who don't grasp the bigger picture, but at the end of the day, when it comes to warranty they are your only option and if you don't force the issue when it comes to difficult dealership employees, VW can't be made aware of issues to know if there's a common fault that needs updated parts or software fixes or anything. With a new car, you really do need to utilize the dealer system until that warranty is up, otherwise collectively the cars don't get developed or don't get good fixes/updated parts down the line to fix common issues.
