A simple UOA will not show if the oil has too much soot, a TBN & TAN will help, but in reality you need to look at the sump and oil pump intake screen to see if the OCI was too long.
The oil in a petrol engine is gold to start with, then turns more of a dark brown. If it turns black the detergents have run out or the block was already sludged up to start with.
If the oil filter has blocked, the insolubles will go out of limits, but just to confuse things that UOA figure also increases if the active detergents have been used up.
Using too much Moly (Mo) laden oil additives will also darken the oil.
The oil in a petrol engine is gold to start with, then turns more of a dark brown. If it turns black the detergents have run out or the block was already sludged up to start with.
If the oil filter has blocked, the insolubles will go out of limits, but just to confuse things that UOA figure also increases if the active detergents have been used up.
Using too much Moly (Mo) laden oil additives will also darken the oil.