Today i removed UIM and noticed dirt in vacuum line including solenoid and check valve. It's like soot.
Also i tested check valve and it's leaking under pressure/vacuum.
So i have several questions:
1. Is it normal?
2. Did check valve became cause of dirt or check valve broke because of dirt?

 

air filter s arent perfect , and if you dont change them regularly / clean them this may very well happen , hell even if you do change and clean them this will still happen LOL . check your TB it may be dirty as well .

 

I changed filter about month ago and i don't think it's just dust.
Sorry, i forgot to attach image.

 

yeah , but changing the filter doesnt clean the dirt that was already in there .

 

I understand : )
But after rebuilt only 300km past and i didn't see this dirt before

 

check for vacume leaks