c/diesel-mechanics

Am I the only one who sees guys torquing head bolts dry?

I was helping a buddy in his shop in Boise last month, and he was putting a head back on a Duramax. He just slapped the bolts in and started cranking. I had to stop him. You absolutely must use the right lube on the threads and under the washers, every single time. The torque spec in the book is based on a specific friction coefficient you only get with the factory lube or a proper substitute. Doing it dry gives you a false torque reading and can lead to uneven clamping force or a blown head gasket down the road. I learned this the hard way on a 6.7 Powerstroke about five years ago. I had to pull the head twice in six months before an old timer at the parts counter set me straight. What specific lube do you all use when the factory stuff isn't available?

Hit 500 hours on my scan tool and it made me rethink my whole approach

I always thought the fancy diagnostics were just for the big shops... but seeing that number made me realize how much time I've saved not just throwing parts at problems. It finally clicked when I used it to find a weird CAN bus fault on a 2020 Freightliner that would have taken days the old way. Anyone else have a tool that changed how you work on the newer stuff?

Stopped at a farm auction in Iowa and saw a 1980s Mack truck with a homemade fuel system

I was at a farm sale near Des Moines last month and they had an old Mack R model for auction. When I looked under the hood, someone had put in a custom fuel line setup using clear plastic hose and hose clamps. It was feeding straight from the tank to the pump with no real filter in line. I could see bits of junk floating in the fuel. What's the worst homemade fix you've seen on a diesel engine?

Finally got a stubborn 6.7 Powerstroke crank seal to seat after three tries and a trick with a heat gun

This was on a 2015 F-350 in the bay last week. The new seal kept walking out just a hair when you tapped it in, enough to leak. After the second failure, I remembered something an old timer said once. I warmed the aluminum housing with a heat gun for about two minutes, just until it was uncomfortable to touch. Froze the new seal in the shop freezer for 20 minutes. The temperature difference made it drop right in with a solid thunk, no walking at all. Let it normalize for an hour before starting. Has anyone else used a similar trick on press fits, or is there a better way you've found?

Tried a different torque sequence on a 6.7 Powerstroke head gasket

Always did the factory pattern, but a guy in a shop in Boise swore by a modified sequence he called the 'star from the center out'. Did it on a rebuild last month and the surface contact looked way more even with my straightedge. Anyone else mess with torque patterns on those engines?

Serious question, I used to think a 3/8 drive was fine for everything on a 6.7 Powerstroke

Last week in the shop, I was fighting a seized caliper bolt on a 2019 F-250 and my 3/8 impact just clicked. My buddy tossed me his 1/2 inch Milwaukee and it zipped it right out. I guess I've been making things harder on myself for years. Anyone else have a stubborn bolt that finally made them switch up their go-to tool?

That phantom coolant leak on a 6.7 Powerstroke had me chasing my tail for two days

It was a 2015 F-250 that came in with a slow drip. I pressure tested the system, checked the usual spots like the water pump and radiator, found nothing. Finally pulled the turbo to get a proper look and spotted a tiny crack in the EGR cooler, a spot you just can't see from below. All that time for a part the size of my fist. Anyone else had a coolant leak hide in a spot that dumb?

Warning: Heard a guy at the truck stop in Billings say he never uses a torque wrench on injectors...

Said he just goes by feel after 20 years. I always use my 1/2-inch Snap-on digital wrench and follow the spec sheet. Has anyone else run into this mindset on the road?

I always thought a 3/4 inch drive was overkill for most truck lug nuts

My buddy Jake at the shop in Tacoma showed me his torque log after a week of doing wheel seals on a fleet of F-550s. He was hitting spec in half the time with less strain on his arms using his big Snap-on 3/4, while I was fighting with my 1/2 inch. What size breaker bar do you guys run for daily heavy truck work?

Chat with an old timer at the truck stop in Flagstaff changed how I check for blow-by

He told me to pull the oil fill cap with the engine hot and at a high idle, not just at a low idle like I always did. I tried it on a 6.7 Powerstroke that seemed fine before, and you could see a steady pulse of vapor I had missed. How many of you guys check it that way, or is that just for older engines?

Serious question, everyone swears by the 15-minute flush on a Detroit 60 series after a head job.

Did one in a Kenworth at a Phoenix shop last year, followed the book, still got a coolant leak from a warped deck. Now I run the engine for a full hour before I even think about buttoning it up. Anyone else skip the short flush?

I'm seeing a lot of guys skip the torque sequence on head gaskets lately

Watched a tech in our Denver shop just go in a circle, and that engine was back for a coolant leak within a month. What's the most important step you think people rush through?

Question about the new DEF systems on the 2024 trucks

We just got a 2024 Freightliner Cascadia in the shop, and the DEF system is totally different from the 2022 models. The filter housing is now a single unit, and the dosing valve is integrated. It took us a full day to figure out the new diagnostic codes, which was a pain. Has anyone else run into this, and what's the best scan tool for these new setups?

Serious question, has anyone else had success with a heat gun on a stubborn injector?

I was working on a 6.0 Powerstroke in a shop in Boise last week, and the number 8 injector was absolutely seized. I tried the usual puller and penetrant for an hour with no luck. On a hunch, I borrowed a buddy's Milwaukee heat gun and applied steady, focused heat to the injector body for about three minutes. It came free with a normal puller on the next try, no damage to the bore. What other tricks have you all used for this specific problem?

Had a 6.0 Powerstroke with a persistent high-pressure oil leak, tried the 'freeze plug' trick with a 10mm socket and some RTV as a last resort.

Working on a 6.7 Powerstroke in a flooded shop parking lot changed my whole approach

We had a flash flood in Houston last spring, and I had to replace a high-pressure fuel pump on a customer's truck standing in 8 inches of water. Some guys say you should never work in those conditions, but getting that rig running for a family that needed to evacuate felt right. Where do you draw the line on working in bad conditions versus turning a job away?

Spent $800 on a fancy diagnostic scanner for the shop and it's been nothing but trouble

Bought the 'Pro-Diesel 9000' last month thinking it would cut our diagnostic time in half on these new emissions systems. It freezes up constantly, gives false codes on common rail pressures, and their tech support just tells you to reboot it. What's the most reliable scan tool you guys actually use day in and day out?

Had to pick between a reman or new turbo for a 6.7 Powerstroke in a farm truck.

Customer's F-350 was down with a blown turbo. Gave them the choice: a $1200 reman unit with a 1-year warranty or a $2200 new OEM one. They went with the reman to save cash. It's been six months and the thing is already making that same high-pitched whine. Anyone have a good source for new turbos that doesn't break the bank?

Tried a new torque wrench on a head gasket job and the difference was huge

I was doing a head gasket on a 6.7 Powerstroke last week and decided to compare my old clicker wrench to a new digital one I borrowed. The old wrench felt fine, but the digital readout showed I was off by almost 15 foot-pounds on a few bolts during the initial pass. I went back and re-torqued everything with the digital tool, following the exact three-step sequence. The engine fired up clean with no leaks, which wasn't always the case for me on these jobs. Has anyone else made a switch like that and noticed a real improvement in consistency?

Had a guy bring his 6.7 Powerstroke in for a rough idle. He'd been cleaning the MAP sensor with brake cleaner for a year.

Just compared a 12-point socket to a 6-point on a rusted Cummins ISX manifold bolt

Had a job on a 2012 Freightliner in Boise last week where the old 12-point socket just rounded off the bolt head. Switched to a 6-point impact socket and it came right off with no slip. The extra contact points made all the difference on that crusty steel. Anyone have a go-to brand for 6-point sockets that can take the heat?

Changed my tune on using a torque wrench for every injector job

I used to think the 'good and tight' method was fine for injector hold-down clamps, especially on older 12-valve Cummins engines. Then I had a truck from a farm in Billings come back twice in a month with the same injector weeping fuel. After the second time, I actually torqued them to spec with my Snap-on wrench, which was 25 foot-pounds. The leak stopped completely and hasn't returned in six months. I guess that extra 5 foot-pounds of precision actually matters for the copper washer seal. Anyone else get burned by skipping the torque wrench on what seems like a simple job?

Vent: My uncle, a retired heavy equipment guy, told me I was overthinking a Paccar MX-13 oil leak

He just said, 'Kid, you're chasing ghosts, it's always the rear main seal on those after 200k miles.' Has anyone else had an old-timer drop a line that saved you a ton of diagnostic time?

Shoutout to the old guy who taught me about injector timing on a Detroit 8V92

Three years ago in a shop in Spokane, I was ready to just swap the whole rack on this screaming Jimmy. He walked over, showed me how to adjust the timing with a dial indicator, and saved me a $3,000 parts bill. Anyone got a favorite trick for those old two-strokes that the manuals don't mention?

Appreciation post: An old timer at the Detroit Diesel plant set me straight on torque specs

I was putting together a Series 60 head and thought I could just go by feel, but this guy named Carl saw me and said 'Kid, you're gonna warp that deck if you don't follow the 50-75-100 ft-lb sequence exactly.' He made me redo it with his calibrated wrench. Now I always use a torque wrench and the factory manual, no shortcuts. What's one piece of advice that changed your basic routine?