Metal Shavings from Vanos Unit?

[Jimbosz07]

Hi all, I have an 03 M3 with 173k miles. It was a cheap car and has a well used past but over the last year of ownership and 3k miles it’s turned into my weekend track car. I recently did rod bearings and the full subframe job and have shop receipts of the Vanos unit being replaced by a shop at 156k.

I got the car very cheaply because it was having Vanos issues again that I intermittently solved with valve body cleaning. Codes were primarily electrical.

At a recent track day I was getting P0013/0014 codes and attempted removing the solenoid pack and cleaning the connection which worked in the past. I thought I saw some glitter on the towel that I used to wipe the oil that drained out on the vanos sealing plate but wasn’t sure. Buttoned it up, drove it home with the codes still returning.

Pulled the valve body again at home and sure enough, there are metal shavings I wiped off the valve body. Paper towel pictured below. Shavings are not magnetic.

I pulled and cut open the oil filter expecting to find accumulation and was surprised to see virtually none.

Is there something aluminum that can deteriorate in the Vanos unit/valve body that could explain this?

My only other thought is that when I did the rod bearings I could see evidence of the oil pump chain rubbing the oil pickup (which is common from what I’ve read) but I assume that pickup is iron and would therefore be magnetic? I’d also expect that to be found in the oil filter rather than manifesting itself so greatly in the Vanos unit.

Any and all input is greatly appreciated!

[sapote]

1. Is there something aluminum that can deteriorate in the Vanos unit/valve body that could explain this?

2. My only other thought is that when I did the rod bearings I could see evidence of the oil pump chain rubbing the oil pickup (which is common from what I’ve read) but I assume that pickup is iron and would therefore be magnetic? I’d also expect that to be found in the oil filter rather than manifesting itself so greatly in the Vanos unit.

1. The parts that can have wear and tear are the vanos 2 pistons for pushing/pulling the splined shafts; the 4 pistons in the pump disk, the solenoids in the valve block. The pump disk/pistons are metal, so only the vanos 2 pistons/cylinders are aluminum.
2. The oil condition in the engine pan doesn't cause vanos issue as there are multiple filters before the cleaned oil eached the vanos.

[maupineda]

I would pull the unit out and do proper inspection. Also the roller bearing for the pump disc may have failed

[Slideways]

Like the oil pump mesh screen or the engine oil filter, I'd expect that filter to catch metal debris before it enters the VANOS system.

Edit: Sounds like the oil pump disc gets oil first from the cylinder head, generates 100 bar oil pressure and then gets to the pressure regulator:

VANOS system hydraulic operation:
• When the engine starts, oil from the main engine oil pump is fed under pressure to the
pressure reducing valve.
• The oil pressure is dropped to approximately 0.5 Bar and fed to the radial piston high
pressure oil pump.
• The pump is driven by the exhaust camshaft and the 100 bar pressure is built up by the
pressure regulating valve. The volume of pressurized oil is stored in the accumulator
supplying both adjustment pistons. Both pistons are held in the default position by the
high pressure oil.

Unfortunately, this picture does not show a cutaway of the pressure regulator or valve body:

[sapote]

A failed roller bearing would destroy the aluminum housing but the debris cannot reach to the solenoid block, but they all fell into the oil pan, including the contaminated oil.