Tiny flecks of aluminium in oil filter

Tiny flecks of aluminium in oil filter

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bmwmike

Original Poster:

1,968 posts

53 months

Sunday 18th August
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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 smile

227bhp

9,508 posts

73 months

Monday 19th August
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bmwmike said:
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 smile
I don't usually cut open the traditional metal type unless there is a real need to as its messy, but it's always useful to have a look inside any. You can actually buy special tools that are like can openers to do it, but I spin them on the lathe and use a parting tool to get in.
I disagree that you have to cut a cartridge type, you just part the pleats and look in, oil flows from the outside to in. You can tear off the end caps if you like to unravel it for a pic, this is the current mystery one:



If i'd known, I would have got a better pic.

The problem is (as per this thread) when something like this happens as there is generally only two places it can originate from and that is the crank bearings or it was left in there from machining when the engine was originally built., maybe an outside chance it's cam related. As it's aluminium it's soft, so relatively non-damaging. Crank bearing material is usually in flat flakes it it's run low on oil and wiped the crank a few times too many.

I've found a few unexplained things in sumps, one type of engine often has some small black round granules in the sump with a plastic feel to them, even when they've been rebuilt and come back in for a refresh or inspection. Last week I found a very tiny and thin blue disc in one, the only thing I could liken it to is what's left over when you take a hole punch to a bluey-clear plastic bag, but it was smaller than that so who knows confused I've yet to find a spanner or something useful.

The engine I mentioned back there ^ is a Duratec, it's come out of an old (scrap) car, but is going to be rebuilt to make more power and go back into something else. Duratecs are known for the oil rings sticking on the pistons, the engine then goes from one which doesn't need the oil checking to one which consumes it at a fast rate. This is an engine where 'full dealer service history' is meaningless.
This also happens with just a normal healthy engine when it's a bit old and no-one checks the oil for a long time too of course.

The owners don't realise so it runs low and the crank takes a swipe at the bearing, maybe when just cornering now and again.
What happens then is always different and on a scale of 1 - 5 of severity and depends on various things happening.
I've known them to run absolutely perfectly, no noise or anything, yet found bearing material in the filter:



Which lead to the sump coming off, some of the big-end bearings found to be ragged and replaced in situ, I even know which cap to go for first to find the most damage.

Some take a bigger swipe out of the bearing:



Which leads to a light knock under load, often on cold start. Again, these can get away with just new bearings.

Then there are those which run dry under duress or for a long time, the soft bearing material has gone by now so the steel backing then grabs the crank and spins in the rod, that's when it gets serious and it's new engine time.







So the Duratec is quite durable, some older engines with larger bearing clearances and lower oil pressures won't put up with that kind of abuse, oil starvation or contamination by abrasive particles for any reason and that's it, game over for crank, bearings and even more if left to run.

The annoying thing in your instance is we'll probably never know where the metal is coming from, although (looking at the pic again and now some years on) I'm thinking unlikely crank bearing working surfaces, definitely not pistons, maybe the chap who mentioned the cam area has it, but as per my ramblings above elude to, you need a specialist of this engine.



Edited by 227bhp on Monday 19th August 10:44

bmwmike

Original Poster:

1,968 posts

53 months

Monday 19th August
quotequote all
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.