Blackstone Oil Analysis - High Aluminum

[Edwardsc1]

Would anyone have some insight or thoughts on this oil analysis I just got back from Blackstone? I have a 2015 50i with the N63TU engine. Blackstone noted double the average aluminum values in my oil. I had just under 5k miles on the oil and right around 69,500 miles on the car. Any thoughts would be appreciated!

[tlow98]

Hmmmm. Some of the fluid bearings in the head are aluminum. Lots of thins in the valvetrain touch aluminum. Kind of A tough one.

Side note - 10 quarts of added oil in 4,300 miles. Holy crap.

[zhp pilot]

Surely that 10 qts of added oil is a typo, maybe it should be 1?. If not, I think some higher than normal aluminum is a secondary concern at this point.

[Tomcat_F15_STL]

Chain guides gone?

[yupetc]

The intake camshaft bearing caps could be a suspect. And in our case with the N55's, there aren't any real bearings with the camshaft. The shaft journal just sits inside the half round housing from the head and the other half round housing are the caps themselves. And boy I'll say this, I've worked on 4 heads so far which are minimum of 70k miles each, and a common find I always observe is the caps are always VERY scratched up. There's oiling holes from the head half, but the caps are just non-oil caps, so if the oil has any bit of dirt or debris, it can go in there and end up on the cap side and create some scratches.

Look at this blog and refer to the pictures for the cap wear:
https://bmwtechnician.com/2017/10/25...haft-bearings/

When I took mine out, I find much worse wear on mine (@190k miles, henceforth a full rebuild). On assembling everything back, I sanded the caps grooves and smoothen it out, then took it to the blast cabinet to oxide blast the surface for MicroSlick Cerakote. Then after 6k miles, took the caps out again to check for wear, caps 0 and 1 have had the Cerokote worn out a little bit, but 2 through 6 are all intact. And goes to explain why when I do see this wear, they are mostly on cap #1, and some on #0. Anyway, if you're having this same problem, chances are that you won't even notice it from the way it drives, until it's too late where the camshaft starts to really grind down on the cap. But as far as having that much aluminum debris in the oil can point to many things; and this could be one of them.

[tlow98]

Originally Posted by yupetc

The intake camshaft bearing caps could be a suspect. And in our case with the N55's, there aren't any real bearings with the camshaft. The shaft journal just sits inside the half round housing from the head and the other half round housing are the caps themselves. And boy I'll say this, I've worked on 4 heads so far which are minimum of 70k miles each, and a common find I always observe is the caps are always VERY scratched up. There's oiling holes from the head half, but the caps are just non-oil caps, so if the oil has any bit of dirt or debris, it can go in there and end up on the cap side and create some scratches.

Look at this blog and refer to the pictures for the cap wear:
https://bmwtechnician.com/2017/10/25...haft-bearings/

When I took mine out, I find much worse wear on mine (@190k miles, henceforth a full rebuild). On assembling everything back, I sanded the caps grooves and smoothen it out, then took it to the blast cabinet to oxide blast the surface for MicroSlick Cerakote. Then after 6k miles, took the caps out again to check for wear, caps 0 and 1 have had the Cerokote worn out a little bit, but 2 through 6 are all intact. And goes to explain why when I do see this wear, they are mostly on cap #1, and some on #0. Anyway, if you're having this same problem, chances are that you won't even notice it from the way it drives, until it's too late where the camshaft starts to really grind down on the cap. But as far as having that much aluminum debris in the oil can point to many things; and this could be one of them.

Fwiw, this is how every aluminum head BMW is designed. Bummer that the n55 is showing issues in this way.

[Edwardsc1]

Originally Posted by tlow98

Hmmmm. Some of the fluid bearings in the head are aluminum. Lots of thins in the valvetrain touch aluminum. Kind of A tough one.

Side note - 10 quarts of added oil in 4,300 miles. Holy crap.

The 10 quarts was definitely a typo, I would be extremely concerned if I had to add anywhere close to that much. It should have been 1 quart. It was really 2 quarts by the time all was said and done, but I am wondering if the dealership did not fill it all the way when I first got the car. I got a Low Oil Warning light like a week after I bought it.

[Edwardsc1]

Thanks everyone for your insights, I'll be keeping an eye on it through the next oil change to see if anything changes. I have not heard any strange noises, so it's just a waiting game at the moment