Old timer at a Cummins shop set me straight on oil change intervals

I was at a buddy's garage last week getting some injectors swapped out, and this grizzled guy who's been turning wrenches since the 80s overheard me talking about changing oil every 10,000 miles on my 5.9. He just laughed and said I was throwing money away and actually wearing out the engine faster. Told me he swears by 5,000 mile intervals with a quality conventional, and he's got a million miles on his old 12-valve to prove it. That got me thinking, maybe all these synthetic marketers are just selling fear. I've been following that 10k rule for years, but now I'm wondering if I've been doing more harm than good. Anyone else get told something similar by an old timer that made you question everything?

2 comments

2 Comments

paulw637d ago

Throwing money away and wearing out the engine faster" - that's an old school take for sure. I've run synthetic in my trucks for years and never had a problem stretching it to 8-10k, oil analysis always comes back clean. I figure modern engines and oils are way better than what those 12-valves were dealing with back then.

noah8806d ago

What kind of oil analysis are you running, like Blackstone or just a basic TBN check? I'm curious if the extended intervals catch anything with fuel dilution in those newer engines versus the 12-valve crowd. I've seen guys swear by 5k intervals on older diesels but never bothered with testing to back it up lol.