Hello, I recently purchased a B8200 which hadn’t had any maintenance performed in quite some time. I changed engine oil and transmission. I was working the tractor the next day and after about 1/2 hour the engine began knocking with the oil light on. I shut down immediately, waited a few minutes started up again and ran well for 10-15 min. Then the knocking again with oil light on. At that point I shut off again and waited. Then I just went back to the barn. A local diesel mechanic suggested adding a small amount of Marvin Mystery Oil to the engine and let the tractor run for a time. Then change oil and filter. He said krud may still be in the system and may impede oil getting where it needs to go. The Mystery oil would help clear out the krud. Can anyone confirm this or provide a different perspective? Thanks!