Hi all

Recently I've changed my radiator to a new one and upper & lower hoses to ,but I noticed something weird .
I found small rubber pieces every time I checked and something like small particles. It's not head gasket failure , head is very good , engine block was stored for months but I operated it 3 month ago.
i checked and changed cooling water for 4 times in 2-3 months and this issue still exist.
​​​​​​​any help will be appreciated ❤️

 

The only thing I can think of is possible debris that got into the block while it was stored?

 

Can you put up a couple more different pictures of the debris? That one looks like super dark oil to me, like from a diesel...