c/diesel-mechanics

Heard a guy at the fuel island say his 6.7 Powerstroke was 'bulletproof' after a delete

I was grabbing coffee yesterday and overheard two guys at the pump. One was bragging about how his deleted truck was now 'bulletproof' and would run forever. It made me stop and think about all the trucks I've seen come in with melted pistons or blown turbos from bad tunes, even after the emissions gear was gone. The delete fixes one set of problems but can create a whole new list if you don't know what you're doing. It's not a magic fix, it's just moving the weak point. How do you guys explain the real risks to customers who just hear the hype?

I used to think a hot engine was the best time to check for leaks

For years, I'd run a rig hard, then crawl under it with a flashlight to spot drips. Last month in Phoenix, I was chasing a phantom oil leak on a Duramax and saw the fresh oil just vaporizing on the hot block before it could drip. A veteran tech told me to let it cool overnight and check for crusty residue instead. Now I feel dumb for all the time I wasted. What's your go-to method for finding those sneaky leaks?

Can we talk about how much torque a Cat C15 actually makes?

I was reading an old service bulletin from 2005 and it said the peak is 2050 lb-ft, which is just a crazy number to think about. Has anyone here ever dyno'd one and seen it hit that mark?

Stopped a 6.7 Powerstroke from eating injectors with a simple fuel pressure check

Had a 2015 F-250 in the shop that kept killing number 3 injector every 8,000 miles like clockwork. Instead of just swapping parts, I hooked up a gauge and found the low pressure fuel pump was dropping to 45 psi at idle. Replaced that $300 pump first, and the truck's been solid for over a year now. How many of you actually check rail pressure before just throwing injectors at these things?

Stripped a bolt on a Cummins ISX oil pan in a freezing shop bay at 2 AM.

I welded a nut onto the bolt shank, let it cool for a minute, and it came right out with a standard wrench, saving a huge headache and a tow bill. Anyone have a better trick for dealing with seized fasteners in tight spots?

Stopped at a truck stop in Flagstaff and saw a driver trying to fix his own DEF system with a garden hose

I was fueling up my service truck on I-40 last month and saw a guy under his Peterbilt with a regular green garden hose. He had it shoved into the DEF tank fill neck and was just letting it run. I mean, I get that DEF is mostly water, but city tap water? I walked over and asked him what was up. He said his truck was derated and a 'buddy' told him to flush the tank with water to clean the crystals out. He'd already put about five gallons in. I tried to explain about the 32.5% urea mix and how tap water minerals would wreck the injectors and sensors, but he wasn't having it. Has anyone else had to talk a driver down from a truly bad roadside fix idea? What's the worst you've seen someone try?

Visiting the old Mack yard in Allentown made me realize we've gotten too reliant on scan tools for basic diagnostics.

Seeing a guy there fix a persistent low-power complaint on a '97 RD688S just by tracing a fuel line with his hands and finding a soft spot proved that sometimes the old-school feel is still the best tool you have.

Had a 2012 Ram 2500 with a persistent crank-no-start that stumped me for a whole weekend

Turns out it was a corroded pin in the ECM connector I only found after pulling the whole harness. Anyone have a better method for tracking down gremlins like that?

Switched from a basic code reader to a proper diagnostic laptop for a 6.7 Powerstroke and the difference was night and day.

I was chasing a persistent P0087 fuel rail pressure code on a 2015 F-250 for a customer. My old handheld scanner just gave me the code and basic data, which pointed me at the usual suspects: pump, regulator, lines. I spent two days swapping parts, guessing, and getting nowhere. Then I borrowed a buddy's laptop running the full factory diagnostic software. In about 20 minutes, I could watch the high pressure pump command versus actual pressure in real time, graph the injector flow rates, and see a sensor signal that was just slightly out of spec under load. The handheld told me 'something is wrong'. The laptop showed me exactly *what* was wrong-a failing pressure sensor giving a lazy signal-and saved me hours of labor and a ton of parts cannon money. Has anyone else made that jump to full computer diagnostics, and what was the first problem it solved for you?

I laughed at the guy who said to use a heat gun on a seized turbo actuator, but he was right

For years, I was sure you had to pull the whole turbo unit if the VGT actuator was frozen solid. Last month, a guy at a shop in Tacoma told me to just hit it with a heat gun for a solid minute, then try the key. I thought he was crazy, but I was stuck on a 2012 Duramax and gave it a shot. After heating the actuator housing, I cycled the key and heard it click free for the first time in weeks. Saved me half a day of work and the customer a big bill. What's the most 'backyard' fix you've seen that actually works on these newer engines?

PSA: A guy at the Wyoming truck stop showed me a trick for stuck injectors.

He told me to put a little ATF in the fuel filter housing and let the lift pump push it through for about 30 seconds before cranking. It worked on a stubborn 6.7 Powerstroke that had been sitting for a year. Anyone else have a go-to method for this?

Found out the Detroit 60 Series could run on 100% biodiesel with just a kit

I was reading an old service bulletin from a shop in Spokane and they mentioned installing a conversion kit for a fleet of trucks. It let them run straight B100 in the winter without gelling, which I thought was impossible for that engine. The kit was basically just a heated fuel line and a different filter housing, cost about $1200 per truck back then. Has anyone actually done one of these conversions on a Series 60, or is it more trouble than it's worth?

Spent 8 hours chasing a phantom oil leak on a 6.7 Powerstroke

The customer said it was dripping from the rear main, so I pulled the trans in my shop in Boise. Turned out to be a tiny crack in the oil cooler housing up top, dripping down the back of the block. The whole job should have been a 2 hour fix, not a full day. Anyone else had a leak that sent you on a wild goose chase?

A guy at a truck stop in Flagstaff told me he never uses a torque wrench on injector lines, just 'feels' it. That still bugs me.

My $300 thermal camera finally paid off on a stubborn coolant leak

I bought it for electrical work, but it showed a tiny temp difference on a lower radiator hose that I never would've felt by hand. Anyone have a go-to method for those slow seeps that doesn't involve dye?

Just hit 500,000 miles on my personal truck's original injectors

I was doing the math on my service records (you know, the ones I actually keep for my own stuff) and the odometer crossed that mark last Tuesday. I've been running the same set of Bosch injectors since the truck was new, which honestly surprised me given some of the fuel we get around here. Anyone else have a rig that just refuses to quit on a major component?

Vent: Bought a cheap aftermarket DPF filter for a Duramax, huge mistake

Spent about $350, half the OEM price. It clogged solid in under 3 months, threw constant regen codes. Had to buy the proper one anyway and eat the labor cost. Anyone know a decent mid-price brand that actually holds up?

The time a 6.7 Powerstroke oil cooler job turned into a three-day nightmare

Last Tuesday, a regular customer brought in his 2015 F-250 with the classic coolant-in-oil issue, so I quoted him for the usual oil cooler swap. The problem was, the previous shop had used some kind of red threadlocker on every single bolt (like, every single one), and I spent over 12 hours total just heating and coaxing them out without stripping anything. What's your take on using threadlocker on parts that are supposed to be serviceable, especially on a known failure point like this?

Honestly thought those magnetic oil drain plugs were a total gimmick

Tbh, I put one on my personal 7.3 last winter just to see. Pulled it after 5,000 miles and it had a decent amount of fine metal fuzz stuck to it, which the regular plug never caught. Anyone else run these long-term on high-mileage rigs?

I finally hit 500 hours on a single set of injectors in a 6.0 Powerstroke

I was working on a 2005 F-250 that a local farmer uses for hauling. After I did the full bulletproofing kit three years ago, I just checked the data and those original injectors are still running strong at 500 hours post-work. I honestly thought they'd need replacing after 300, given the history of that engine. It shows how much a proper flush and updated FICM tuning can extend their life. Has anyone else seen injectors go this long after a full rebuild, or did I just get lucky?

I bought a cheap knockoff torque multiplier for a stubborn crank bolt and it snapped clean in half after two uses.

Spent a full day chasing a phantom coolant leak on a 6.7 Powerstroke

I had this 2015 F-250 in the bay with a slow coolant loss, no obvious puddles. My first guess was the usual suspect, the water pump, so I swapped that out. Still losing coolant. Pressure tested it, held fine cold. It wasn't until I got the truck up to full operating temp and let it idle for almost an hour that I finally saw it. A tiny, fine mist was coming from the lower radiator hose connection at the block, only when everything was hot and expanded. The factory clamp had just lost its spring over time. In my experience, you always check the easy stuff first, but this one hid until everything was heat-soaked. That simple clamp cost me about eight hours of diagnostic time. Has anyone else had a leak that only showed up under specific hot conditions like that?

Just realized how much less a modern diesel engine weighs than the old ones

I was reading an old service manual for a 90s 7.3L Powerstroke the other day (you know, the paper kind). It said the engine alone weighed over 900 pounds. Then I looked up the specs for a newer 6.7L Powerstroke, and it's almost 200 pounds lighter. Found that in a tech bulletin from a couple years back. Makes you think about all the aluminum and compact designs they use now. Anyone else run into a spec that made you stop and think about how the job has changed?

Been torquing injector lines wrong for years until a smoke test showed me

I was working on a Duramax with a rough idle last week, and I was sure it was a bad injector. I pulled the lines, swapped a suspect one, and put it all back together. The problem got worse. I did a smoke test on the intake, and I saw a tiny wisp coming from the base of one of the lines I just touched. Turns out, I've been using the 'snug plus a quarter turn' method from an old boss, but on these newer high-pressure common rail systems, that's not enough. The spec is a specific torque, like 22 foot-pounds, and then a second angle torque. I was leaving them just a hair loose, enough to let in air under load. Felt like a real idiot... but at least I know now. Anyone else have a torque spec story that changed their routine?

Tried a new torque wrench on a Detroit Series 60 head job after my old one gave out

My old clicker wrench was a cheap one from a truck stop, and it was always a bit of a guess. For this rebuild, I grabbed a Snap-on TechAngle from the tool truck, set it to 310 ft-lbs for the main caps. The digital angle readout and the beep made it impossible to mess up, felt way more solid than just waiting for a click. Anyone else made a switch like that and noticed a real difference in confidence on big jobs?