c/diesel-mechanics

Just passed 500 engine rebuilds and it hit me different

I was going through my old job logs this weekend out of boredom and counted up my engine rebuilds since I started turning wrenches. Hit exactly 527 over 14 years in the trade. What got me is the first 200 were mostly 6.0 Powerstrokes and I remember hating every one of those jobs. Now looking back those rebuilds taught me more about diesel fuel systems than any class ever did. Anyone else ever accidentally track a stat like that and realize how much experience you actually have?

That old timer who insisted on torquing oil pan bolts by feel

Met a retired CAT mechanic in the break room at a truck stop in Oklahoma, and he swore torque wrenches were for people who didn't trust their own hands. He reached over, snugged my filter housing bolt with a half-inch ratchet, and said 'feel it click in your wrist, not your tool.' Any of you old school guys still skip the torque wrench on non-critical stuff?

Just realized hand tools have changed more than I thought

I was working on an old 5.9 Cummins yesterday and had to pull the injectors. My young helper handed me a new puller with a fancy slide hammer. I told him to go get my old Snap-On injector puller from the 90s. That old thing worked smooth as butter while his new one kept slipping off the threads. Has anyone else noticed older tools just fit better on these older engines?

Had a master tech tear into me about using impact guns on injector hold-down bolts

Ngl, I used to just zip those injector hold-down bolts down with my 1/2 inch impact like everyone else in the shop. Then this old guy from down the bay, must have been 30 years in the trade, watched me do it on a 6.7 Powerstroke last Tuesday. He pulled me aside and said I was destroying the threads and crushing the copper washers unevenly every single time. Honest to god I thought he was just being a boomer about his tools. But I tried it his way with a torque wrench and a breaker bar on the next injector job, a Cummins ISX 15. The difference was insane, no fuel leaks on startup, no fighting stripped holes. Now I feel like a clown for all the comebacks I probably caused over the years. How many of you actually torque these down by spec or do you still send it with the gun?

Just found out 6.0 Powerstroke heads actually need to be torqued differently than the book says

I was rebuilding a 2004 F-250 last month and like always I followed the factory service manual for head bolt torque sequence. Got everything buttoned up, fired it up, and it started puking coolant out the back of the passenger side head gasket within 10 minutes. I was pissed. Tore it back apart and called an old buddy who's been doing these since they came out. He told me the manual's torque sequence is wrong for the later revised head bolts because the metallurgy changed. Found a thread on Powerstroke.org with actual ARP engineers explaining the updated specs. They recommend a different pattern and an extra 20 ft-lbs on the outer bolts. Second time around with the corrected numbers, no leaks and it's been running strong for 3 months now. Anyone else run into factory manuals that are just flat out incorrect for these trucks?

Tried a bypass oil filter kit on my Ford 7.3

I put on a bypass oil filter kit from OilGuard about 6 months ago on my 2002 Ford 7.3 Powerstroke. Instead of cleaner oil, my oil analysis came back way worse with higher wear metals than before the kit. Anyone else have a bypass filter setup actually mess up their oil readings?

For years I never flushed coolant on my old Cummins, now I do it every two years

I used to think changing coolant was a waste of money. Just top it off and keep going, right? Then last spring I had a 5.9 start puking out the water pump seal after 180k miles on the original green stuff. The corrosion inside the block was terrible, took me a whole weekend to flush it all out with a chemical cleaner. Now I use Fleetguard ELC and change it every two years without fail. Anyone else had a similar wake-up call with neglected coolant?

Had to pick between a reman injector and a junkyard pull for my 6.0 last month

My '06 F-350 started missing bad on cylinder 4. I had $400 to spend. A reman was $450 from the local shop, but I found a used injector off a wrecked truck with 80k miles for $80. I gambled on the junkyard one cause I was broke. It's been 3 weeks and it's still running smooth, but I'm waiting for the other shoe to drop. Anyone else taken that risk and regretted it?

Tried a fuel additive I was skeptical about on a 7.3 Powerstroke

Picked up some Hot Shot's Secret EDT Plus on a whim last week for my buddy's 2000 F-250 that's been cranking slow on cold mornings. Figured it was snake oil but after two tanks the starter doesn't drag near as bad and it fires right up at 30 degrees. The cetane boost must actually do something on these old HEUI injectors. Anyone else have luck cleaning up injector stiction with additives or am I imagining this?

Had a talk with a 20-year veteran that made me rethink my torque wrench habits

Ran into an old timer at the parts counter in Boise yesterday... guy had hands like a bear paw. He told me he never uses a torque wrench on lug nuts just goes by feel after 40 years. I laughed but then he showed me a wheel he saw fly off last month because someone overtorqued with a fancy digital unit. Made me wonder if I'm trusting my clicker too much... has anyone else had a seasoned mechanic tell you to ditch the gadgets?

Chased an injector knock for 8 hours before I found the real issue

Turned out to be a cracked fuel return line letting air in, not even the injector itself. Has anyone else had a simple fix hide behind a loud symptom like that?

Just realized my torque wrench was off by 12 ft-lbs after a Cummins rebuild went sideways in Atlanta

I was torquing head bolts on a 6.7 ISB outside a shop in Buckhead and the engine dumped coolant everywhere, turned out my Snap-on wrench was clunking at 85 when it should've been 97, has anyone else had their calibration drift without noticing?

Found out my shop's air dryer was costing me $200 a month in wasted power

I was looking at our electric bill last month and noticed it was way higher than normal. After some digging with a clamp meter, I found the air dryer was cycling nonstop because the purge valve was hanging open just a crack. That little leak was dumping compressed air 24/7 and running up the bill by about $200 a month. Has anyone else tracked down hidden power drains in their shop equipment?

That cheap coolant I swore was junk saved a blown head gasket on an old Pete

I had a 1995 Peterbilt 379 come into my shop in Des Moines about three years ago with a head gasket that was already weeping. The owner insisted on using some generic green coolant from Tractor Supply instead of the name brand stuff I always recommend. I about told him he was wasting his time and money, but he had me flush and fill it anyway. Well that truck is still running on the same gasket today with over 80,000 more miles on it, and I have to eat my words every time I see that bottle on the shelf. Has anybody else had a cheap fluid or part actually hold up better than expected?

Hit 500 injectors rebuilt in a year and it caught me off guard

I was going through my work log last night and realized I hit 500 injector rebuilds since last March. I do a lot of Cummins and Detroit stuff out of my garage in Akron, and I didn't think I was moving that fast. Most of them were for the same three fleets, so I guess word got around. Has anyone else tracked their numbers like that and been surprised by the total?

I finally found that coolant leak after 3 days of hunting it down

Was working on a 2015 Freightliner Cascadia last week, the one with the Detroit DD15. Owner said it was losing a gallon every 200 miles but no puddles anywhere. I spent 2 days checking hoses, water pump, head gasket, all the usual spots. Finally on day 3 I got under it with a pressure tester and a flashlight while the engine was hot. Found a tiny hairline crack on the back of the EGR cooler tube, right where it rubs against a bracket. Couldn't see it unless the engine was at operating temp and the metal expanded just right. Slapped a new tube on and it held pressure fine. Anyone else had a leak that only shows up when the engine is hot?

PSA: 3 fuel filters in 2 months taught me a nasty lesson about algae in diesel

I run a 2012 F-350 for my hauling gig. Last fall I started getting rough idle. Threw a filter on it. Cleared up for two weeks. Then it clogged again. Took the old filter apart. Saw black slime. That's diesel bug. Algae grows in water sitting in the tank. Especially if your truck sits for days like mine. I ignored it for too long. Now I'm running biocide and draining the separator every week. Has anyone else had this stuff ruin a filter overnight?

The day I saw an engine that looked like it sat in a swamp for 30 years vs 6 hours later

Overheard a kid at the parts counter say turbos are just 'fancy hair dryers'

I was picking up some oil filters at the Cummins dealer last Tuesday and this young guy maybe 19 or 20 was arguing with the counter guy. He said he didn't need a new turbo for his 7.3 because they're just 'fancy hair dryers that push air into the engine.' The old parts guy just stared at him for a solid 10 seconds then laughed. I had to bite my tongue because I've heard that joke before but he seemed dead serious. It got me thinking about how many guys actually understand what a turbo does versus just slapping one on because it sounds cool. Has anyone else run into customers or younger mechanics who completely miss how basic diesel engine systems work?

Warning: compared OEM injectors to reman ones on a 6.7 Powerstroke and the difference was brutal

Spent $1200 on remans from a local shop and had two fail within 6 months, then swapped to factory Bosch injectors for $2200 and the truck runs smoother than it did when it was new, so has anyone else just decided to bite the bullet and never mess with non-OEM parts again?

Remember when injector cups were actually reusable?

Spent 45 minutes yesterday fighting a seized injector cup on a Series 60 that would have popped right out with a pry bar back in '04, and now I'm wondering who decided we needed to replace them every single time instead of just cleaning them up and running with what we had?

TIL those cheap ultrasonic injector cleaners actually work

I spent 10 years thinking they were a gimmick, but my buddy at Johnson Trucking in Omaha let me try his on a 6.0 Powerstroke that had a rough idle and it smoothed right out. Anyone else had good luck with a sub $200 cleaner?

Saw a fleet of new electric garbage trucks in Seattle last month and it's a joke

I was up there for a job and saw three of them parked behind a city depot. They look like regular trucks but with a giant battery pack where the diesel should be. The city claims they save money, but the mechanic I talked to said they're down for service twice as often as the old Internationals. He showed me a work order for a battery coolant leak that took three days to fix because they needed a specialist from California. How is a city supposed to keep trash pickup on schedule with that? Has anyone else had to deal with this electric heavy equipment nonsense yet?

My kid asked why we don't just fix the old trucks instead of always buying new ones. It hit different.

Update: I was dead wrong about using a torque wrench on every single bolt

Spent 5 years thinking it was overkill for smaller jobs, but after snapping a head bolt on a Cummins ISX last month and costing myself $800 in repairs, I finally get why the old guys swear by it. Anyone else have a tool they ignored for way too long?