My new to me B7100 is ready for an oil change. The PO had it fully serviced (all oils, filters, etc) by its original dealer at 1080 hours before I bought it. I have the receipt from the service, $582 worth! I am now at 1159. The manual calls for 30 wt or 10w30. The dealer had used 4 qts of 15w40. It has not used any oil over the last 70 hours I have used it. I am from the old school where if it is running well, don't change the type of oil, ie, weight or brand. So I am inclined to go back with 15w40. Any other opinions?
John
John