I had this older guy Bob stop by my bay last week while I was working on a Cummins ISX. He watched me tighten down the injector hold-downs and said 'you're going too fast, you gotta let the threads settle'. I always just zipped them down with the torque wrench in one smooth motion. Now I do it slow, let it sit for 10 seconds, then finish the turn. No more random leaks since then. Anyone else had a veteran call them out on something obvious?
Was working on a 2015 Freightliner Cascadia last Tuesday, oil dripping bad after a long haul. I checked the pan gasket, the cooler lines, even the rear main seal. Nothing. Three hours in I was about ready to throw my wrench. Turned out it was a tiny crack in the turbo drain tube, hidden behind some wiring harness. A $40 part cost me a whole day of labor. Has anyone else spent way too long chasing a simple leak on these trucks?
Back in 2018 I was struggling with a stubborn 6.7 Powerstroke injector on a hot June day. He walked over, didn't say much, just handed me a specific length of 3/8 inch breaker bar and said 'use this, not your impact.' That one tip has saved me stripped threads and headaches on at least 15 jobs since. Anyone else had a mentor give them a simple tool swap that totally changed their process?
I was out on a farm near Lubbock last Tuesday with a Powerstroke that wouldn't start. Got a fuel pressure reading of zero at the bowl, so I figured the HPOP was toast. Pulled the valve covers, tested everything, even started pulling the passenger head bolts. Then I noticed a tiny wet spot on the back of the #4 injector where the return line was split. Fixed it for $12 in fuel line and it fired right up. Has anyone else spent half a day chasing a problem that turned out to be something simple?
Back when I started at a fleet in Lubbock, a retired mechanic named Joe told me to switch to a citrus degreaser instead of dunking parts in diesel. I ignored him for two years until I developed a nasty rash on my hands that wouldn't go away. Has anyone else had skin problems from using diesel as a cleaner, or is it just me?
I used to be that guy who would just smash ring terminals onto battery cables with a hammer and call it good. Did it for like 5 years on customer trucks because I figured tight is tight right? Then last December I had a 2016 Kenworth T680 come back to my shop in Tucson with a no-start. Found the main positive cable end hanging loose at the starter. I had put that on 3 months earlier. I felt like an idiot when I saw it. Now I use a proper hydraulic crimper for anything 4 gauge or bigger. Cost me $150 but I havent had a single cable fail since. Anyone else ever cheap out on crimping and regret it later?
Overheard two guys at the shop yesterday arguing about this. One said he saves about $400 by rebuilding a set of Cummins heads instead of buying reman units. The other guy swore he had a valve seat drop at 20k miles on a rebuild and lost a whole engine from it. I've done both ways myself but I still go back and forth on which is smarter. How many miles do you guys usually get out of a set of rebuilt heads before you start seeing issues? Or do you just swap and forget it?
After 10 years I finally bought a torque wrench for oil changes and realized I was cranking them down way too tight based on feel alone so how many of you actually torque to spec versus just going by the ugga-dugga method?
Guy named Pete, been doing this since the 70s, watched me crank down an injector on a 5.9 Cummins and just shook his head. Said I was overtorquing by a good 15 ft-lbs and that's why I kept getting copper washers to leak after a few months. Switched to a click-type torque wrench instead of my beam style and started following the exact sequence he showed me. Has anyone else had an old school mechanic call them out on something that made them work different?
Last March I had a 2018 Ram 3500 come into the shop in Boise with a coolant loss problem. I spent three days chasing a leaky water pump and even replaced the radiator hoses. The customer kept coming back every two weeks saying it was still losing coolant. Finally my foreman looked at it and pointed out a tiny bubble trail near the back of the head on cylinder 6. That head gasket had been failing the whole time and I missed it because I was so focused on the front end. Anyone else ever completely miss a head gasket sign because you got tunnel vision on something else?
My buddy at a shop in Nashville kept raving about his $200 bore scope and I figured it was just another gadget to waste money on. Then I pulled a head on a Cummins ISX last month and spotted a crack in the liner wall that I would have missed completely without being able to zoom in and twist the camera around. Anyone else find that these things actually save more time than they cost?
Had a guy roll into the shop last Tuesday with a '94 Cummins 12-valve, coolant pouring out. He swore it was my fault from a oil change I did 4 months ago. Pulled the head and found a crack right between cylinders 3 and 4, had nothing to do with me. Showed him the crack with a flashlight and he still argued for 10 minutes before paying. Anybody else get blamed for stuff that was already broken?
I bought a set of reman injectors off a parts house online six weeks ago for my 5.9 Cummins. Stuck number 5 in without checking anything, just bolted it on and fired it up. That cylinder ran rough as hell, knocking like crazy, turned out the injector was stuck closed from the factory. Lost an afternoon of labor and had to pull it back out, plus shipping for a replacement. Has anyone else had bad luck with reman injectors or is it just me?
I always thought those inline pre-filters were just extra money for no reason, figured the main filter catches everything anyway... but my buddy Jake in the shop showed me the crud that came out of a tank after a month with one on. He said the stock filter can't stop water and fine grit from wearing injectors down early, and he showed me a cut-open filter element that proved it. It hit different seeing that gunk with my own eyes, like how much crap is really floating around in bulk diesel. Has anyone else run a pre-filter setup and seen a difference in injector life?
I see it all the time on forums and in shops. Guys let their trucks idle for 5 to 10 minutes after a hard pull before they kill the engine. This was true for the old mechanical injector pumps but modern common rail systems with electronic injection don't NEED that cool down like that. In fact I watched a guy at my shop in Tulsa burn out his turbo seals last year doing exactly that. He would drive in hot idle for 8 minutes then shut it down. His VGT turbo had oil coking issues at 80k miles. I know this because I pulled the turbo myself and found the oil passages partially blocked. The real trick is to let it idle for 30 to 60 seconds tops. Anything more is just wasting fuel and heat soaking the top end. Has anyone else actually torn down a turbo and seen the damage from long idling?
Was hauling a trailer full of scrap and temps shot up to 240 before I caught it, ended up cracking the head between cylinders 3 and 4. Anyone else had luck with aftermarket heads holding up better than OEM on these trucks?
I spent 12 hours straight trying to get a seized 3406E out of a 2002 Pete 379 last week. The rear motor mount bolt snapped off flush with the block and I had to drill and easy-out it at a super awkward angle. Guys at the shop were useless because they were all busy on other rigs. Has anyone else had a job just fight you every step of the way like that?
I had been struggling with injector cup seals leaking after replacement for months. This guy with 30 years on me watched me yank an injector and said I was twisting too hard on the way out. He showed me to wiggle it side to side with a steady pull, no twisting. First time I tried it on a 6.7 Powerstroke, the seals came out clean and no leaks after. Has anyone else had a bad habit a senior guy corrected that saved you money?
Used to just feel my way around the back of a 6.7 Powerstroke injector pump with my fingers and hope the bolts lined up. After 3 failed attempts in one afternoon last June on a 2010 F-250, I finally caved and bought a cheap borescope from Harbor Freight for 40 bucks. Now I can actually see the bolt holes and the alignment marks without pulling the whole intake manifold off. Only took me a decade to learn this lesson lol. Anyone else got a tool they resisted buying for way too long?
I used to swear by those ultrasonic cleaning machines for injectors. Quick and easy. But after three sets came back with the same rough idle within 6 months, I started pulling them apart and cleaning the screens and orifices by hand with a small pick and brake cleaner. It takes twice as long but I haven't had a single return on that job since last April. Anyone else find the manual way holds up better on high-mileage engines?
I used to just listen for a consistent spray pattern on injectors and call it good. But last year I finally bought a digital pop tester that gives me actual pressure numbers. Turns out three of my last five rebuilds were off by 50-100 psi even though they sounded fine. Now I won't touch an injector without running it on the gauge first. What about you all, do you still go by sound or have you switched to digital testing too?
I kept going by feel (you know, the old ugga-dugga method) until I finally looked it up at 18 ft-lbs and now I'm wondering how many other bolts I've been over-tightening on these older motors, has anyone else actually snapped one of those little bolts before?
Old timer named Dave at the shop told me to stop putting 15W-40 in the hydraulics on my 2008 Cat backhoe. I thought he was being picky but after 6 months the seals started swelling and the bucket was moving slow. Switched to the right hydraulic fluid and it fixed it in a week. Anyone else have a guy give you advice you ignored at first?
Old diesel tech named Mike at the Cummins dealer told me to stop using the puller and just freeze my injector cups before installation. Tried it on a 5.9 job last Saturday and they slid right in with zero hassle. Anyone else tried the freezer trick or still swear by the tool?