I finally got a Cat C15 to stop smoking after a rebuild

This Cat C15 came in with blue smoke after a full overhaul. We thought it was ring seal or valve guides. After rechecking everything, I spotted a tiny crack in the turbo oil feed line. Replaced the line and the smoke cleared right up. It was such a relief to nail down the issue. Sometimes it's the small stuff that gets overlooked. Feels good to have a win after a tough job.

4 comments

4 Comments

piperbailey2mo ago

Oh man, talk about a needle in a haystack moment after all that work. You do a full rebuild, your brain goes straight to rings or valves, and it's just this little hairline crack letting oil sneak into the turbo the whole time. It's gotta be the most annoying kind of win, where you're happy it's fixed but also kinda mad you didn't see it first. At least it wasn't something that meant tearing it all down again. Those little mystery fixes are so satisfying to solve, even if they make you feel a bit silly.

davis.david2mo ago

Jessica's mirror trick saves so much time, lol

the_jana2mo ago

Yeah, that mirror thing is no joke. We had a 6.7 Powerstroke with a phantom oil leak after a top end job. Spent two days convinced it was the rear main. One of the lube techs finally got under it with a little inspection mirror and found a cracked oil cooler line fitting you couldn't see from any normal angle. Felt like an idiot but also saved a transmission pull for nothing.

jessica1302mo ago

Our shop foreman always said to assume it's the big stuff first after a rebuild. This C15 story and what piperbailey said about feeling silly but relieved totally flipped that for me. Now I make the guys check every external line and fitting with a mirror before we even talk about opening it back up. Saved us last week on a ISX with a weepy coolant connector.