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Switching to synthetic oil saved my Cummins after 200k miles
For YEARS I used conventional 15w40 in my old 5.9, figured it was fine. Then at 215k miles I started hearing a tick on cold starts, got worse over 3 weeks. Pulled the valve cover and found sludge caked around the rockers and pushrods, real bad. Swapped to full synthetic Rotella T6 and a new filter, now 30k miles later the tick is gone and oil comes out way cleaner. Has anyone else seen this kind of sludge buildup from sticking with conventional too long?
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victorhill26d ago
Did you @hayden144 end up using the T6 too? That Rotella stuff is pretty good. I had a buddy with a Chevy 350 that was full of sludge and he just dumped in some high mileage synthetic blend and it loosened up enough gunk to block his oil pickup screen. Took him a weekend to drop the pan and clean it out. Not saying that'll happen to everyone, but that's why I always stick with one brand once I pick it.
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Did you flush the system at all before you put in the T6, or just drain and fill? I've heard mixed things about switching to synthetic on a high-mile engine, some folks say it can loosen up deposits and cause leaks in places that were sealed by sludge. Curious if you had any issues with that or if it was a straight swap.
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