[Guy]

Blackstone was very prompt when I dealt with them this summer. The report was in depth with footnotes specific to my engine and application. If the report comes back as no coolant in the oils as I hope it does, they also will inform you to other contaminants such as combustion by products , possibly due to ring failure. You are on the road to solving your mystery. Blow by is very common in high mileage engines, but not in the coach applications