c/diesel-mechanics

I used to swear by impact guns for pulling stuck injectors until I switched to a slide hammer setup last year

For like 5 years I'd just crank the torque up on my 1/2 inch impact and hope for the best on stuck injectors in old Cummins 5.9s. Then I wrecked a cylinder head on a 2001 Dodge in Baton Rouge because the injector sleeve came out with it (huge mistake). Now I use a Proto slide hammer with a threaded adapter and some Kroil oil let it soak overnight first. Has anyone else had better luck with slide hammers over impacts for this kind of job?

Chased an air leak on a Cummins ISX for 3 days straight

I had this 2015 ProStar in the shop last week, it was surging at idle and throwing a P0471 code. Checked the usual stuff, MAP sensor, wiring, even swapped the EGR valve. Turned out to be a tiny crack in the intake tube right where it connects to the turbo, I couldn't even see it until I had someone rev it up while I sprayed soapy water everywhere. Three days man, three days of my life over a 20 dollar hose. Has anyone else wasted that much time on something that simple?

Worst week I've had in 10 years of working on trucks

Last Wednesday I was swapping a transmission on a 2015 Freightliner Cascadia and the damn thing slipped off the jack. Broke my left big toe and cracked the bell housing. Then on Friday a customer argued with me for 20 minutes about a oil leak I fixed that turned out to be a loose drain plug he messed with. I lost about 8 hours total that week between the injury and the back and forth. Has anyone else had a week where everything just went sideways for no good reason?

Switched from hammering out freeze plugs to a puller set 2 years ago, never looking back

Debate: Should I stay old school or go electronic on injector pop testing?

Had a chat with a guy named Pete at the parts counter yesterday who swore his digital pop tester saved him two hours on a 6-cylinder job compared to my old mechanical way... he said I'm wasting time counting sprays by hand. But I've been doing it that way for 15 years and never had a comeback on a rail. Do you think the newer electronic testers are worth the extra cost or is it just another way for shops to charge more for the same results?

Hit 1000 oil changes without a single mistake today

Ive been working at a fleet shop in Omaha for 3 years now and just hit my 1000th oil change with zero screw ups. Never double gasketed a filter or forgot to tighten a drain plug or anything like that. Anyone else keep track of stuff like this or am I just weird about my numbers?

Finally got that Cummins ISX to fire after 4 hours of diagnosing

I was on a job outside Birmingham last Tuesday and the ECM wouldn't talk to my laptop at all. Turned out to be a chafed wire behind the intake manifold grounding out the data link. Has anyone else had a bad ground cause a no-comm issue on these newer engines?

I finally switched from traditional fuel filters to the newer spin-on type after a bad experience on I-75 last summer

For 20 years I used the old canister style filters on my Peterbilt. Didnt see any reason to change. Then last August I was hauling a load of lumber from Atlanta to Nashville and the truck started losing power near Chattanooga. Pulled off at a truck stop and found the O-ring on the canister had dried out and cracked. Took me over an hour to clean up the mess and get a new seal. A younger mechanic there had the spin-on type on his rig and said he swapped them every 30k miles with zero issues. So I converted my truck over last October. Not as cheap up front but way less hassle on the road. Has anyone else made that switch and noticed better reliability?

Had the worst string of injector jobs last month that nearly broke me

Last month I had three trucks roll in back to back with injector issues, and every single one fought me. First was a 2008 Cummins ISX where the injector cups were seized so bad I spent 6 hours just on extraction. Tried every trick I knew, heat, penetrating oil, even a slide hammer, and still had to drill one out. Then a Detroit Series 60 came in with a stuck injector that snapped the hold down bolt before I even got it loose. Ended up having to pull the head on that one, which turned a 4 hour job into a full day and a half. Third truck was a newer Volvo D13 where the harness had rubbed through on the valve cover but the customer swore it was injectors. I charged him for the diagnosis but he was pissed I didn't just throw parts at it. Best week I had this year was last Tuesday when a guy brought in an old 5.9 12 valve that just needed a fuel shutoff solenoid, in and out in 45 minutes and he tipped me $40. Anyone else have a month where the universe just decided to test you on injectors?

Just realized the hard way that injector return lines can bleed air for days

Was chasing a no-start on an '02 Ford 7.3 at a ranch outside Bozeman, and it took me three days to figure out the return lines were letting in micro bubbles. Has anyone else fought phantom air in the system after replacing just the supply side?

That Cummins ISX rebuild taught me a tough lesson about torque specs

I was out near Cheyenne last winter doing a head gasket on a fleet truck. Got everything torqued down by the book, but she started sweating coolant after 50 miles. Turned out the block threads were worn from a previous overtorque and my readings were off. Had to helicoil three holes and start over. Anybody else run into block thread issues on high-mileage ISX motors?

Learned a hard lesson about fuel filters on a job near Bakersfield

I was working on a fleet of Peterbilts out by the Grapevine last summer. Truck kept dying going up the hill, customer was furious. After two hours of chasing injectors and pumps I finally swapped the primary fuel filter. It was clogged with algae even though it looked clean from the outside. The filter had only been on there 3 months too. Has anyone else had that green slime show up way faster than expected?

Spent $90 on a "high-end" fuel filter and learned a costly lesson

I bought a fancy Donaldson fuel filter for my 2012 Cummins last month, thinking it would be better than the OEM part. After 3 weeks, it started letting air into the system and cost me a tow to the shop near Tulsa. Turns out the gasket was a different thickness and I should have just stuck with the factory Fleetguard filter. Anyone else had a bad experience with aftermarket filters on a 6.7?

TIL why my old mentor hated impact wrenches on injector cups

Back in 2018 at Pete's Diesel in Omaha, I used to zip out injector cups with my 1/2 inch impact every time... thought I was saving time. Took me 3 years and a cracked cylinder head on an old Cummins ISX to realize how much harmonic stress I was putting on the block. Now I only use a breaker bar and torque wrench, even if it takes twice as long. Anyone else have a tool habit you had to unlearn the hard way?

That moment my injector cup tool slipped and cost me 4 hours on a 6.7 Powerstroke

I was working on a 2015 F-250 out in Charlotte last Tuesday, pulling the injectors on a 6.7 Powerstroke. Everything was going smooth until I went to pop the cup out and my cheap tool slipped, cracking the cup lip. Ended up having to pull the whole fuel rail and soak the thing in PB Blaster for 2 hours before I could get a grip on it. Took me until 7 PM to get it back together, way past my quoted time. Has anyone else had luck with those OTC injector cup pullers or should I just bite the bullet on a better set?

PSA: That 'simple' oil leak on a 6.7 Powerstroke might not be the turbo pedestal

Just spent 12 hours chasing what everyone online said was a classic turbo pedestal leak on a 2015 F-250. Replaced the whole unit, only to find the leak was still there... It turned out to be a tiny, almost invisible crack in the valley pan itself, right near the back. All the oil was just running forward and making it look exactly like the pedestal. Had to pull the turbo again to get to it. Has anyone else been tricked by a leak in that spot, or am I just having a bad week?

Hot take: I was wrong about those aftermarket DEF heaters for the cold

I always told guys at the shop in Fargo to just stick with OEM parts, thought the cheap ones would fail in a month. Then my own truck's factory heater died last winter and I threw a $120 Dorman unit in as a quick fix. Two years later, that thing is still working through negative 30 degree nights without a hiccup. Anyone else run into a cheap part that just won't quit?

I swapped from a cheap $20 parts washer pump to a Graymills and the difference in cleaning power was like night and day.

After three months of fighting with the cheap one clogging on every other job, the Graymills unit blasted through a caked-up set of injectors from a 6.7 Powerstroke in under ten minutes, so what's your go-to for cleaning really nasty parts?

Got a wake-up call about fuel quality at a truck stop outside El Paso

I was driving a service truck back from a job in New Mexico last fall. Stopped at a big truck stop just off I-10 to fill up the rig. The place looked fine, but about 20 miles down the road, the engine started running rough and lost power. I pulled over and found water in the fuel filter bowl. The whole system was contaminated. It took me and my apprentice four hours on the shoulder to drain the tanks, swap filters, and bleed the lines. The boss was not happy about the tow bill. Now I carry my own clear jar to do a quick visual check on fuel before I pump, no matter how legit the station looks. Has anyone else had a bad fuel experience make them change their routine?

Spent two days chasing a no-start on a 6.7 Powerstroke that ended up being a bad ground strap

The truck had a new FICM and good batteries, but it just cranked with no fire. I finally found the main ground from the block to the frame was corroded under the insulation, which was a first for me. Has anyone else had a ground issue cause a no-start without throwing a single code?

I know everyone swears by the 3/4 inch impact for lug nuts, but mine failed on a job in Boise and I had to improvise.

Used to set injector timing with a dial indicator and a prayer

On the old Cat 3406, we'd pull the valve cover, mount the indicator, and turn the engine by hand. Took half a day. Now my shop in Boise uses the ET software. Plug in, follow the prompts, done in twenty minutes. Miss the hands-on feel, but can't argue with the speed. Anyone else still break out the old tools for teaching the new guys?

Watching a new guy fight a stuck injector for an hour with a slide hammer changed my mind

He was soaked in sweat and diesel before I handed him my $40 Lisle puller. It popped out in two minutes flat. Why do shops still push the old brute force method when the right tool is so cheap? Anyone got a better puller they swear by?

That stupid plastic clip on the fuel line for a 6.7 Powerstroke had me ready to break something

The truck came in with a slow leak and the usual disconnect tool just bent. I was about to cut the line when I remembered an old timer in the shop saying to heat a small flathead with a torch for two seconds. Did it, slid it in, and the clip popped right off without a scratch. Saved a $200 line and an hour of my day. Anyone got a better trick for those things?

Just watched a 6.4 Powerstroke's oil cooler go from clean to completely clogged in under 10,000 miles.

This was on a customer's truck that does a lot of short trips and idling. Pulled the cooler at 5k for a different issue and it was fine. Came back for a rough idle and coolant mixing, pulled it again and the passages were almost solid with sludge. The only change was the owner switched to a super cheap 'universal' coolant and stopped using the coolant test strips. The before-and-after difference in that short time was shocking. Has anyone else seen a specific additive or maintenance skip cause a failure this fast?