I recently bought an Mk2 TT-S with fairly high miles (185k km or 115k mi), got the car at a good price due to the high miles, buying as-is, and possibly the low demand from covid. It has a CDMA EA113 engine, it's a 2013 MY car.
Despite the high miles the car drives really nice, everything is smooth, DSG is great... I did my homework on the car as well as having an indy mechanic do a PPI, everything looked good at time of purchase. Car needed brakes and CHML (3rd brake light) to pass safety (all done) and everything else was good. I mean it will need some major maint. items done, and it has a lot of stone chips on the front due to the mileage, but I was well aware of all this when I bought it. Mag ride will need to be changed out as well but that's fine with me too. Car is not pristine but I didn't pay for a perfect car either, so not at all regretful.
After purchase I was (and still am) all smiles. The one surprise that did get me was when I drained the oil after purchasing it. Noticed sparkly copper (or brass) specs in the oil filter and then when I looked at the drained oil in the sun it was clearly "glittery"
No big chunks or flakes just very fine "glitter" like particles, a lot of them. Car drove (and still drives) great so there was nothing really to point at any engine issue...there's no noise like rod knock and while the injectors are pretty loud and there's some amount of "sounds like a diesel" going on, I'm quite certain it's not a bottom end noise because rod knock is pretty unmistakable and increases a certain way with RPM such that this does not. Plus I think the mechanic (a VW/Audi specialist would have noticed rod knock as well when the PPI was done).
Still thinking it might be worn rod bearing(s), I started by checking the compression. Found good compression all around--#1 is slightly lower at ~175 while the other three cylinders are between 180-185, but this is both good and within spec for variance. As a side note the spark plugs seemed like they were near new, so I think they were changed not too long ago. Valve cover gasket is leaking a good bit on #1 but that shouldn't affect compression anyway and I'll be changing that soon too.
After the comp test I put each cylinder at TDC and did the "push down" test with a long screwdriver to see if there was any play in the rod bearings. I couldn't get any of the pistons to move down. So it doesn't seem like a rod bearing issue? I have yet to send the oil for UOA but still have it in the bottle I put it in to and got some Blackstone kits recently.
Since then I drove the car daily for a couple months before parking for the winter--no issues and I was more concerned the timing belt might let go since I don't think it was done (I bought all the timing belt stuff including the cam chain and tensioner already but not changed yet). TBH I might not have been as concerned about the copper as I should have been but nothing went wrong knocks on wood. Still it would obviously not be nice to have the engine fail in the near future.
I did a search and found only a couple threads including this one:
www.vwvortex.com
Which didn't seem to really come to any conclusion or solution.
Questions:
1. Could it still be rod bearing(s) wear despite not having any play in the pistons?
2. If it is rod bearing wear, can the bearings be changed on this engine without removing the engine?
3. What else could it be? Turbo thrust bearing is brass I know that, but seems like a lot of copper to be that, plus wouldn't I be having turbo/boost issues in that case?
4. Any other ideas? Should I drop the oil pan before driving it next year? I figure the answer is "yes" but maybe someone has other insights...
Despite the high miles the car drives really nice, everything is smooth, DSG is great... I did my homework on the car as well as having an indy mechanic do a PPI, everything looked good at time of purchase. Car needed brakes and CHML (3rd brake light) to pass safety (all done) and everything else was good. I mean it will need some major maint. items done, and it has a lot of stone chips on the front due to the mileage, but I was well aware of all this when I bought it. Mag ride will need to be changed out as well but that's fine with me too. Car is not pristine but I didn't pay for a perfect car either, so not at all regretful.
After purchase I was (and still am) all smiles. The one surprise that did get me was when I drained the oil after purchasing it. Noticed sparkly copper (or brass) specs in the oil filter and then when I looked at the drained oil in the sun it was clearly "glittery"
Still thinking it might be worn rod bearing(s), I started by checking the compression. Found good compression all around--#1 is slightly lower at ~175 while the other three cylinders are between 180-185, but this is both good and within spec for variance. As a side note the spark plugs seemed like they were near new, so I think they were changed not too long ago. Valve cover gasket is leaking a good bit on #1 but that shouldn't affect compression anyway and I'll be changing that soon too.
After the comp test I put each cylinder at TDC and did the "push down" test with a long screwdriver to see if there was any play in the rod bearings. I couldn't get any of the pistons to move down. So it doesn't seem like a rod bearing issue? I have yet to send the oil for UOA but still have it in the bottle I put it in to and got some Blackstone kits recently.
Since then I drove the car daily for a couple months before parking for the winter--no issues and I was more concerned the timing belt might let go since I don't think it was done (I bought all the timing belt stuff including the cam chain and tensioner already but not changed yet). TBH I might not have been as concerned about the copper as I should have been but nothing went wrong knocks on wood. Still it would obviously not be nice to have the engine fail in the near future.
I did a search and found only a couple threads including this one:

Copper flakes in oil
Changed my '06 BPY oil today, noticed large copper flakes in the oil filter and at the bottom of the pan when draining oil. I've already had my HPFP and cam replaced (at 34k miles) now I'm at 71k miles. I've been using Motul 8100 X-Cess 5w-40 for the majority of my oil changes, Motul 502...
Questions:
1. Could it still be rod bearing(s) wear despite not having any play in the pistons?
2. If it is rod bearing wear, can the bearings be changed on this engine without removing the engine?
3. What else could it be? Turbo thrust bearing is brass I know that, but seems like a lot of copper to be that, plus wouldn't I be having turbo/boost issues in that case?
4. Any other ideas? Should I drop the oil pan before driving it next year? I figure the answer is "yes" but maybe someone has other insights...