Coming from the MKV FSI community, this is shockingly familiar
Anyone involved in FSI forums should know by now that it's
crucial to check the thimble style cam follower every 10k miles or so. The funny thing is, everyone brainstorming the problems with our HPFPs believe a roller would be the
solution!
Here's an example of what a busted follower looks like on the FSI. Note the hollowed-thimble follower (lower right) and the disintegration of the plunger/spring on the HPFP (center):
And the ultimate effect on the cam lobes:
There are
hundreds of threads regarding this issue of golfmkv, myfastgti and the vortex. People have been mailing their shredded followers to VWoA, threatening class action lawsuits, and raising just as much of a stink for over three years now but afaik, VW hasn't even released a TSB.
The issues don't seem to be quite as severe when the follower is finally eaten through as with the TDI though. People have even continued to drive for thousands of miles with little more than fuel cuts and rough idling. Still a mess to fix... I've seen numbers of $6k or more for replacing the cam shaft, pump, etc.
I pulled mine at 35k and the DLC was completely gone with a bit of scoring on the metal beneath, looking a just a bit worse than the one on the left:
The different harnesses of metals did play a role in helping the scenario - but not fixing it. If I remember correctly, 06 and some 07s came with a cam lobe that was too hard (or too soft?) that created a frictional incompatibility. This is also a double edged sword; after the follower is chewed through, the cam
lobe is damaged from grinding on the new bits of shrapnel and the plunger from the HPFP. Then once the plunger is eaten through.... boom.
The only "good" thing about the FSI scenario, is this it being a 15 minute/$50 fix. Doens't look so easy or preventable with the TDI. FSI guys have been testing every oil and additive under the sun, and no one has nailed a firm conclusion on lubrication there either.
After seeing this issue in other VWs... instant facepalm.