N52 particles in oil

[2.5tdi]

I have an N52 engine with 175000 km, and last year I noticed small particles in the oil. I performed an oil flush using Liqui Moly and refilled with fresh Castrol 0W40. Now, after 5000 km, the oil looks similar to last year.

The particles are non-magnetic and very small, with no large shavings in the filter. I’ve seen mixed opinions online - some say this is normal, while others don’t. Has anyone experienced something similar? The car runs perfectly fine.

 

[Scooba_Steve]

I’ve seen mixed opinions online - some say this is normal, while others don’t.

I'd suggest sending a sample for oil analysis is going to give you the best answer.

 

[j3nks79]

I’ve seen mixed opinions online - some say this is normal, while others don’t.

I'd suggest sending a sample for oil analysis is going to give you the best answer.

This

 

[Rockhopper]

That looks like “forbidden glitter” to me - either bearing material or aluminium from somewhere (neither of which are magnetic). - it looks nothing like the oil I’ve taken out of any car I’ve ever owned let’s just say!
Spend a few quid on an oil analysis to be sure though.

 

[2.5tdi]

I ordered analysis, will post results as i get them.

 

[2.5tdi]

I got results but i somehow submitted sample for baseline analysis, which i now understand means fresh oil.
I allready wrote if they can review again as used oil.
What do you guys think? Is acid level still to high for used oil? And particle levels?

 

[Rockhopper]

The wear metals numbers seem incredibly low from what I’ve read. Iron at 300 and copper at 30ppm would be on the verge of starting to get worried.

 

[2.5tdi]

So you wouldn’t touch engine yet? I have to change oil pan gasket, should check crank and rod bearings?
What about acid which is flagged red? Is this normal level for oil in use?

 

[Rockhopper]

The acid level is a measure of how "worn out" the engine oil is. They highlight it red presumably meaning that its a bad number!

 

[2.5tdi]

Yeah but i accidentally submitted oil for unused oil analysis. Could be normal for used oil but i dont know, i did write them anyway.

 

[2.5tdi]

I have asked them to check report again correctly for used oil.
Now they have flagged silica.

 

[2.5tdi]

I plan to replace the oil pan gasket this winter. Due to the issue mentioned earlier, I want to at least check the rod bearings (I’ve read that crank bearings tend to last longer, which is why I don’t plan to check them.
If there is no visible damage on the crankshaft, is it possible to proceed without a measuring tool or Plastigage?
I’ve never done this type of job before and would really appreciate guidance from someone with experience.
Additionally, is the oil pump easy to remove?

 

[2.5tdi]

I checked the rod bearings, and I’m glad I did. Some are even more worn out than the one I took a photo of.

 

[BMWZ4MC]

That's not too bad compared with some of the photographs of S54 bearing shells that have been posted in the M forum. At least you have peace of mind now you've changed them.

 

[2.5tdi]

Just in time, I guess. The engine is still not back together as I’m gathering parts, and I’m still unsure whether I should polish the rod journals just for a cleanup. There are a few spots where you can barely feel anything with a nail.
Can someone help me here?

And i’ve been reading the BMW manual and don’t fully understand the section on checking clearance with Plastigage. It says:

“Use the old conrod bolts to check conrod clearance. Tighten the conrod bolts with special tool 00 9 120. Tightening torque 11 24 1AZ.”

The torque spec is 20Nm, followed by 2x 60 degrees. Should I torque the old bolts as if they were new ones?

 

[Rockhopper]

If you can feel it then its too much and needs dealing with.