Tiny flecks of aluminium in oil filter

[bmwmike]

Hi all

Helping a mate with an oil change, BMW n52 engine with approx 40k on the clock. Cut open the filter ends to stretch out and expose the pleats and it had tiny shaving's of alu. Very small with biggest being approx 2mm long but there never the less in every pleat and not a huge quantity. This is the engines 3rd oil change and is running and sounding fine.

Will take the new filter out in 1000 miles or so and inspect but is there ever a valid reason for this to happen or is it bad news? Nothing showed up on magnet.

Thanks

Edited by bmwmike on Friday 21st October 22:12

[bmwmike]

Bit tricky as the flecks are small but here is a big image which hopefully shows it up OK.

https://www.dropbox.com/s/w5m7owlshtpj7gb/20161021...

Thanks!!

[bmwmike]

Thanks for the reply.

I just noticed you need to download the image to view full size otherwise the compression doesn't show them properly. They look like slivers which is what concerned me.

Sounds like nothing to be concerned at though based on your reply. Ive never seen (noticed?) this before so was a bit shocked especially as it's such a low mileage.

Edit this is cars third filter I believe.

Edited by bmwmike on Friday 21st October 23:30

[bmwmike]

Yeah the cams run in the head on these I think..

[bmwmike]

No idea.. sounded ok when I heard it running.

Is it possibly this is swarf left over from manufacture?

[bmwmike]

Sounds like this is somewhere between acceptable and disastrous but closer to acceptable. Turns out it has a warranty but not sure it's worth persuing. I'd be selling too but it's not my car. Will see what the new filter looks like in 1000 miles or so.

[bmwmike]

Just to update.. we took the filter out after approx 5k miles and it contained similar bits but less particles. Engine is running and sounding fine though. Odd one! If a bearing was spun or spinning I'd expect a heck of a lot more material?

[bmwmike]

HJG said:

If a bearing was spinning/had spun then it would not have done another 5K. You'd have a loud knocking and then if not caught quickly enough probably a con rod taking a trip out the block.

I would take a sample of the engine oil and send it away for analysis. Millers offer a good service for this. This will give you a metal content in PPM.

Thought I'd update this. Engine still running fine, no change since this was first noticed. Oil analysis was done and came back with a big thumbs up - nothing to be concerned at.

I guess some engines just shed metal for the fun of it.

[bmwmike]

Thought I'd update this - we looked at latest filter at 69k and still exactly the same quanity and type of alu bits and the engine is running and sounding fine. Engine had two oil changes since I last updated this thread but I didn't wasn't involved in those so didn't see the filters.

If it was cam bearing wear it'd be toast by now surely with Vanos errors at least. From what I've read the journal wears out and the oil pressure drops.

Can't be a spun bearing as it wouldn't last so long .

I was thinking piston skirts but that would screw up the cylinder walls in that time wouldnt it?

It presumably can't produce metal slivers/flecks forever without something failing. Wonder how many other engines do this but the owners never look.

[bmwmike]

227bhp said:

You don't need to cut open many filters these days, they are the already open cartridge type.
9 times out of 10 when there is non-ferrous material in the filter it's been run low on oil and has taken a swipe from the crank bearings. The only one i've ever seen, that 1 out of ten, is one i'm working on now, 120k on the clock and flecks of alu in the filter. The bearings are perfect, maybe too perfect. I'm kind of doubting it, but maybe the engine had new bearings in it at one time, but on opening it everything looked 'factory'.

Why are you working on it out of interest?

Filter is element type but you still need to cut it open to expose pleats.

I always open my filters. Maybe I'm sad

[bmwmike]

Thanks for the info and taking the time to post the pics, really interesting!! I've asked on the BMW forum about n52 bearing ledge failure which is known on this engine. I'd have thought it would happen quicker than this though but who knows. I just find this stuff interesting.

Btw You are stronger than me if you can rip the ends off the paper filters. I have to cut them off with a knife.