mekanik
Senior Member
Back when 15-40 came out in the early 1980's I was sent a Cummins publication on it called: "A technical overview of oil consumption" It basically explained how carbon buildup between and below the piston rings caused liner polishing and oil consumption. 15-40 greatly reduced this carbon buildup. I don't recall the technical details.
During the same time period Detroit Diesel had literature out that claimed using high detergent oils in their engines would cause the compression rings to become stuck in the ring grooves with carbon buildup. Any Detroits I had apart that the rings were stuck in the grooves I would ask what oil they were using and it was usually 15-40 high detergent. Of course these were well worn high mileage engines.
During the same time period Detroit Diesel had literature out that claimed using high detergent oils in their engines would cause the compression rings to become stuck in the ring grooves with carbon buildup. Any Detroits I had apart that the rings were stuck in the grooves I would ask what oil they were using and it was usually 15-40 high detergent. Of course these were well worn high mileage engines.