Chocolate Rocker Arms pre 2019 DECA Engines

[Jools]

I recently had the misfortune to have to have the top end of my engine rebuilt.
Mine is a 2018 build with as I discovered the chocolate rocker arms with the small needle roller bearings in.
It looks like the No.3 exhaust rocker arm needle rollers collapsed locked the outer roller race solid. This was what was causing the
extra noise as it scrapped up and down on the cam lobe!
Lucky for me none of the needle rollers escaped.

The problem started with a missfire when I put the engine under load.
This lasted for about 30 miles and then cleared up.
I scanned the car when I got home and found a missfire reported on cylinder 3.
So either coil pack, spark plug or injector then.
I swapped the coil packs from cylinders 1 & 3 to see if the problem repeated itself and transferred to cylinder 1.

Well it didn't occur again, so all good!

A couple of days later a work collegue said the engine sounded noiseier than normal.
I hadn't noticed as with the sound proofing and radio on you can't really hear the engine unless you boot it.

The sound was like it is at start up before the hydraulic lifters have come up to pressure, but this was after 30 minutes of driving.

So the fault finding started.
1. Plugs out, all OK.
2. Compression test, all in spec.
3. Camera down the cylinders, all looked OK.
4. Camera view of the throttle body, Hmmm, oil on the butterfly, OK?
5. Camera view of the charge cooler, Hmmm, reflections in the bottom of it, water leak?
6. Camera view of the rocker arm, small needle roller type, Hmmm!

All through these tests I was talking to Tomas at VAG Technic, he couldn't have been more helpful trying to bottom it out.

Finally took the risk and drove it carefully over to VAG Technic, who stripped the top end off, found the problem and
put it right.
At the same time the chain tensioners and sliders were replaced. Plus the water pump and camshaft adjuster bolts.
All the usual stuff while the engine is out, that you can't do without taking the engine out.

I have done over 6000 miles since then without it missing a beat!

The reflection in the bottom of the charge cooler I'll do in another thread.

The picture is of an old good (left) rocker arm and the collapsed rocker arm (right) and the cam shaft lobe it scoured in the middle.

[elchet]

With a 47k mile early 2018 (haven't checked the build Sticker but being an early one it's almost sure to have the same needle rocker bearings), I'm wondering about preempting this for peace of mind. How much was the work from VAG Technic?

[Rusty Racer]

Well done Jools, very informative.
I’m assuming the cost is several thousand pounds.
I will definitely be renewing my warranty and speaking to Audi when it’s in for an oil change

[Jools]

At the time it was about £3500 for the rocker arm change only. That was a few months ago though.
Better it contact them direct for an idea and possible time to do it.

[elchet]

The discussion on this over at the audi world forums suggests that Audi (albeit Audi of America) are handling this failure under extended warranties too.

https://www.audiworld.com/forums/audi-a ... 02/page18/

[Rusty Racer]

After a failure… great