Is it normal for this engine during oil changes and how much is too much?

 

You shouldn't be getting any metal particles. Are you sure it's metal and not disintegrated rubber bits from any of the gaskets up top?

 

This was a 3500 mile oil change, it looks like glitter, did cut the oil filter for inspection but it is very clean.

 

Any amount of glitter in the oil is bad and that's a lot of metal particles after only 3500 miles. My guess is rod bearings but if you still have some of the oil left, send a sample off to Blackstone Labs for an analysis and explain the situation. They'll send you a free sample collection kit. Mail it back and they'll do a thorough analysis and tell you, among other things, what metals are present and the most likely culprit. The cost is under $30 and postage should be less than $3. It's well worth it.

 

Don't have any old oil left, just spoke to them and they suggest to wait at least 1500-2000 miles for a proper oil test results.
Not sure if this would be too risky waiting or going for rod bearing replacement now?
I expected to see particles in oil filter but there are none, they can be noticed only on the pan bottom, it is like golden or cooper color.

 

The problem is any metal is going to look golden in color due to the coating of oil so the apparent color doesn't really help. I don't know what your mileage is, but replacing rod bearings in a 2008 may not be cost-effective. It might be cheaper to swap out the engine with a known good one -- or just drive it until the engine fails since the car may not be worth investing a lot into fixing it.. If it were up to me, I'd do what Blackstone Labs suggested, send in a sample after 1500 miles, and see what they say. Any chance it was in the pan before you did the oil change? It is a little strange that you can't find any evidence of metal on the filter element. Perhaps wash the filter element in a bowl of mineral spirits or some other solvent and see if any metal flakes settles to the bottom solvent.

 

It has 126 K, I already invested 2 years ago on alternator bracket and valve cover/timing chain upper seal replacements to eliminate oil leaks so kind of reluctant to let go this engine. I'm the owner since 110 K and one important service that was performed from previous owner is valve stem seals.
So in addition to rod bearing what else could be expected to be serviced at this stage?

 

Results from Blackstone are in, all appears to be normal.
I am not sure if waiting 7700 miles for next oil change will be OK?
Usually I do change the oil every 3500-4000 miles.
On this recent oil change I noticed much less glitter so still not sure if I should go for rod bearing change or wait?

 

They are usually spot on giving suggestions. I would say your interval is low. I run mine to 8k and usually change it a couple hundred later depending on the time I have. They have suggested me going to 9k but I know when I get to 8k I around time for me to change. Having the numbers are definitely reassuring.

 

3500-4000 is a great interval. take care of that aging engine. lots depends on driving habits- if you are doing many short trips then yes, definitely change under 5k. if you are doing long freeway miles then safe to push it over. Also, I got mine from an owner that followed the bmw oil change procedure religiously, and I was shocked with the amount of carbon buildup that this caused inside the engine (oil pan, underneath valve cover).

glad blackstone came back clean. 0ne thing to note- did you run the car and then take the sample soon after, around 1/2 way through the oil draining process? the metal particles tend to fall to settle at the bottom with time, so blackstone recommends the aforementioned procedure.