c/diesel-mechanics

Fixed a fuel leak on an old Cat 3406 outside Amarillo last month

Was on a roadside call near a truck stop and realized a dried out o-ring in the injection pump was the culprit. Anyone else swear by replacing all the o-rings on an older motor before they even start acting up?

Vent: Blew a turbo on 6 hour run to El Paso last Tuesday

Was hauling a trailer of parts down I-10, about 3 hours in I heard this whining noise that got worse fast. Pulled over near Fort Stockton and found the turbo shaft had play and oil was spraying everywhere. Took me 6 hours to limp to a shop and $1,800 for a new unit plus labor. Anyone else had a turbo fail without warning on a long haul?

Had a $300 injector pump fail on me in Iowa last Tuesday - changed my whole view on rebuilding vs buying new

Was sure that cheap torque wrench was fine until I snapped a bolt on a Cummins

Picked up a no-name torque wrench at a pawn shop for $20. Used it for a year, no complaints. Last month I was torquing head bolts on a 6.7 Cummins and it decided to click at 80 ft-lbs instead of 120. Snapped a bolt clean off in the block and spent 6 hours drilling and extracting. That wrench is now a paperweight. Anyone else have a tool fail at the worst possible moment?

Unpopular opinion: Those cheap no-name turbo rebuild kits are actually fine

I spent 15 years swearing by factory parts until I put a $40 eBay kit in a 6.7 Cummins for a guy who couldn't afford the real deal, and it's been running strong for 6 months now. Anybody else had good luck with the budget stuff or did I just get lucky?

Learned 75% of injector failures come from bad fuel filters

Was reading through some Bosch technical bulletins last night and saw this stat. Never realized how many problems could be avoided just by swapping filters more often. Any of you guys religious about filter changes or do you just run 'em till they clog?

TIL that fuel return lines can cause more problems than the supply side

I had a Cummins ISX come in last month with a no-start condition. Fuel pressure was good at the pump, filters were fresh, but it would crank and crank without firing. Did all the usual stuff like checking injectors and wiring before a buddy told me to look at the return line. Turns out there was a restriction in the return line from a kinked hose. That build up of back pressure was keeping the check valves from seating right. Never would have thought a return line could cause that much trouble. Fixed the hose and it fired right up. Anyone else run into a weird return line issue before?

Just lost $300 on a faulty injector puller tool

Bought a no-name injector puller off eBay for a 6.7 Powerstroke job last month. Figured it'd save a few bucks over the OTC kit my buddy uses. First pull on the #4 injector and the threaded rod stripped right out. Spent 2 hours with a torch and a slide hammer getting that injector out anyway. Now I gotta buy the OTC tool plus I wasted a day on labor I can't bill. Anybody else get burned by cheap specialty tools lately?

PSA: I just learned my torque wrench has been wrong for 8 months

I was chasing a weird vibration on a freightliner last week, swapping out u-joints and checking balance on the driveshaft. Nothing made sense until I decided to check my torque wrench against a borrowed snap-on at the shop. Turns out my cheap husky one was off by 15 foot-pounds on the low end. I had been under-torquing everything from wheel nuts to flywheel bolts since I bought it in January. That explains why I had two different jobs come back with loose bolts in the same month. Now I feel like an idiot for not checking it sooner. Has anyone else found their own tools just stopped being accurate without warning?

Discovered a trick to unstick a stuck injector without pulling the head

I had a 6.0 Powerstroke that was running rough after sitting for 3 months. Tried the usual stuff like fuel additives and cracking lines, but injector #8 wouldn't budge. Ended up mixing 50/50 ATF and acetone in a squirt bottle and letting it soak into the rail overnight. Next morning it fired up smooth as butter and I didn't have to pull the head or replace anything. Has anyone else tried this method or got a better way to deal with stuck injectors?

The old-timer who showed me how to prime an injector pump with a soda bottle

I was out on a job near Modesto a few years back, trying to bleed a Cat 3208 that wouldn't catch. An old farmer walked over, saw me cursing at the fuel lines, and handed me a half-empty Mountain Dew bottle he'd cut the bottom off of. He filled it with clean diesel, rigged it up as a gravity feed, and had the engine running in under 10 minutes. I still keep a cut-up soda bottle in my box for those hard-to-prime jobs. Anybody else got a weird field fix that actually works?

Had a injector stick open on a highway off-ramp in Phoenix last summer

I was hauling a loaded trailer down I-10. Exhaust started rolling white smoke. Pulled off at the 32nd Street exit quick. Turns out a cheap fuel filter let water through. Now I always spec Racor filters on any job. You guys ever seen a stuck injector from bad filtration?

The exhaust brake trick on a '98 Cummins that nobody talks about

I accidentally figured out that tapping the Jake brake switch three times fast while holding the throttle at 1500 RPM actually kicks the turbo vane open just enough to clear a stuck solenoid, and I only found it because I was angrily jabbing at it after 45 minutes of roadside troubleshooting near Flagstaff.

Dropped $900 on a "rebuilt" transmission for a 6.0 Powerstroke and it lasted 4 days before it started slipping

I know I shoulda known better but the guy had a shop up in Tacoma and seemed straight up. Said he bench tested it and everything. Fourth day hauling a light trailer up I-5 and it starts slipping in third gear. Called him and he said I probably cooked it by driving wrong. Like what? Now I gotta pay another shop to pull it and I'm out the labor too. Anyone else get burned by a so-called builder that talks a good game but can't back it up?

Wasted $600 on a "lifetime" air filter system that clogged up in 3 months

I run a little mobile diesel repair side gig out of my truck, and I got suckered into buying one of those expensive reusable air filter systems for my service van. The guy at the supply house swore it would save me money over the paper filters because you just clean it and reuse it forever. Well, after about 3 months of driving on dusty gravel roads around farm jobs, that thing was so caked up my turbo was whistling like a tea kettle. I ended up having to buy a whole new filter housing because the gunk warped the seal. So I lost the $600 for the system, plus another hour of labor to swap it back to the regular paper filters. Has anyone else tried those reusable filters and had a bad experience, or did I just get a dud product?

Old timer told me to never trust a reman injector out of the box and I ignored him

Threw a set of six reman injectors into a 6.0 Powerstroke last Tuesday and by Wednesday three of them were stuck open, costing me 8 hours of labor to redo the job with OEM parts, so has anyone else had a bad batch from a rebuilder lately?

That blown injector on I-80 nearly cost me my weekend

Last Friday I was hauling a load of produce from Fresno up to Sacramento when my 2015 Peterbilt started missing like crazy around mile marker 120. Pulled over and could smell raw diesel strong, knew right away it was an injector issue. Limped it to a shop in Modesto and they quoted me $900 to replace just one injector, said the others looked fine. I tried talking them into letting me do it myself in their bay but they said no due to insurance rules. Ended up calling my buddy who runs a mobile repair service and he came out Saturday morning with his diagnostic kit. We found the number 5 injector had a cracked tip and the fuel return line was clogged with debris. Took me and him about 5 hours to swap it out and clean the system, cost me $140 for the injector and $60 for his time and fluid. Anyone else ever deal with a shop that wouldn't let you work on your own rig on their lot?

Old timer talked me into trying a bore scope on a tough job

I always thought bore scopes were just a fancy toy for guys with too much money. But last month I had a 6.7 Powerstroke that kept burning oil and I couldn't find the leak anywhere. A guy at the local parts shop in Boise told me to borrow his cheap scope and look at the cylinder walls. Sure enough I found scoring on cylinder 4 that I never would have seen without pulling the head. Has anyone else had a simple tool change how they diagnose stuff?

Found a weird trick to clear clogged injectors on a cold morning last January

I was working on an old Cummins ISX in a truck stop lot near Omaha when I cracked the fuel return line and let it drip for 30 seconds, and the engine smoothed right out after that - has anyone else tried something like that to save a tow?

Old timer told me I was torquing head bolts wrong on my 6.0 Powerstroke

I've been doing these for like 4 years, always went by the torque spec in the manual. This guy in his 70s watches me for a minute, says I'm not doing the three pass sequence right. Said I was rushing the middle pass. He showed me how he does it, slower and more even. Next one I did, had zero issues with the heads. Anyone else get schooled by some old hand on something basic?

Replaced the oil pan gasket on a 2002 7.3 Powerstroke 3 times before I got it right

Kept slapping RTV on both sides like my old mentor taught me back in '08, but it always leaked at the rear main seal area within a month. Took a trip to a shop in Lubbock last fall and watched a guy put a thin bead on just the pan side and let it tack up for 10 minutes before torquing down - been dry ever since. Anyone else have a simple habit they had to unlearn after years of doing it the same way?

Fought a seized injector for 3 hours on a Freightliner Cascadia outside Phoenix

Had to pull the head because that 30mm socket twisted the injector body into a pretzel, anyone else run into these rust-welded injectors on pre-DEF trucks?

I finally switched from conventional oil to synthetic in my fleet trucks

For years I ran conventional oil in my 2005 Freightliner FLD120 because I thought synthetic was too expensive. Last month I pulled the oil pan on a truck with 350,000 miles and saw sludge buildup that shocked me. My buddy at Cummins in Nashville showed me his fleet data comparing 100 trucks on synthetic vs conventional over 200,000 miles. The synthetic trucks averaged 1.2% better fuel economy and had fewer oil-related repairs. I ran the numbers and the extra $40 per oil change paid for itself in fuel savings alone. Has anyone else made this switch and seen similar results with high-mileage engines?

Why does nobody talk about cracked bell housings on Paccar MX-13s?

I was at a shop in Tulsa last month and saw three trucks in a row with hairline cracks near the starter mount, has anyone else run into that on high-mileage units?

Had a Cat C15 with a stuck injector that took me 2 days to get out

Last month I was working on a 2006 Peterbilt 379 at my shop in Tulsa. The owner said it was running rough and smoking white. I ran a compression test and everything pointed to a stuck injector on cylinder 4. I tried every trick I knew, heat, penetrating oil, even a slide hammer. After 8 hours day one I was ready to pull the head. The next morning I gave it one more shot with a different puller tool I borrowed from a buddy. It finally broke free with a loud crack. The injector bore had some serious carbon buildup I had to clean out with a honing brush. Has anyone else dealt with a stuck injector on a HEUI system where nothing seems to work the first time?