I found an article about super motor oil.
It shows photographs of different engine after oil. The site is in Russian, but it is understandable. It was interesting to see. here's the link: http://moi-nissan.ru/ogo-go/560-kako...vigatelej.html

example:

Which oil to pour more reliable?

 

Oil sludge. Usually this happen if you keep topping up engine oil or due to bad circulation of motor oil in the engine. One way to avoid these is by changing the oil regularly.

 

I want to see what I have in the engine.
It's complicated?
What unscrew?
Conversely difficult to collect?

Who pours some oil?

 

Also to add some people love to add that stop leak in the motor....source another motor and start fresh...you ill find a good solution when it comes down to it, its money and time........Even a bad pcv valve as guy mention above circulation it varies to owner to car

 

Are you speaking English?

 

 

07 Chevy Impala with ~200K. AMSOIL Signature Series 5w-30 changed at 15K intervals in south TX urban driving. No sludge, no varnish...dark areas seen in upper head/valve train is pooled oil, not deposits.

https://maxima.org/forums/group-deal...icants-28.html

 

cool oil