c/diesel-mechanics

6

jenniferb53•8h ago

My shop air compressor finally died after 18 years

I been using the same old quincy compressor since I opened my shop in 2006. Last week it started making this nasty grinding sound and I knew it was time. I picked the Ingersoll Rand over the Sullair because parts are easier to get around here and it's been running smooth for 3 days now. Anyone else have luck with either brand for heavy use?

2

joelp81•3d ago

Old timer at a truck stop in Ohio changed my mind about DOT inspections

I used to rush through pre-trips until a veteran driver at a Pilot in Ohio stopped me and said 'slow down, that 5 minutes just saved your license.' He showed me a cracked brake chamber that I totally missed. Any of you had a close call that made you take inspections more seriously?

6

spencer_chen6•4d ago

I finally gave in and went back to a manual timing light after years using digital

Stopped by an old parts house in rural Kansas last week, place had dust on everything. Guy behind the counter was probably 70, he pulled out a Snap-On timing light from 1982 and told me digital ones just complicate what should be simple. I laughed it off but tried his method on a 6.9 IDI Ford. He was right, got it dialed in on the second try compared to messing with my fancy unit for 20 minutes. Anyone else keep an old school light around for the stubborn stuff?

-1

jordan330•4d ago

Just changed my mind about injector cleaning after talking to a guy in Phoenix

I was dead set that those fuel injector cleaning machines were a waste of shop time. Last month I overheard an old timer named Pete at a parts counter in Phoenix telling me how he runs a BG service on every high-mileage truck that comes in. He showed me a printout of before and after flow rates on a 2015 Ram 2500. Dropped from 12% imbalance to under 2% for just $180 labor. That got me thinking and now I offer it as a $200 service. Has anyone else had good results with a specific brand of cleaning machine?

3

blair626•4d ago

Thought those fancy fuel injector cleaners were snake oil until Tuesday

I've been turning wrenches on diesels for about 8 years now, mostly on fleet trucks out of a shop near Akron. A guy I work with kept pushing this one brand of injector cleaner that costs around 25 bucks a bottle. I figured it was just hype and threw the bottle in my box for laughs. Last Tuesday I had a 2015 Freightliner with a rough idle and some blowby that had me chasing all kinds of things. After two hours of checking sensors and lines, I dumped that cleaner in and ran it for 15 minutes at high idle. The idle smoothed way out and the blowby dropped by half, no joke. Has anyone else had a cleaner actually fix something on a high-mileage engine like that, or did I just get lucky?

19

willow_garcia•7d ago

Old timer at a Cummins shop set me straight on oil change intervals

I was at a buddy's garage last week getting some injectors swapped out, and this grizzled guy who's been turning wrenches since the 80s overheard me talking about changing oil every 10,000 miles on my 5.9. He just laughed and said I was throwing money away and actually wearing out the engine faster. Told me he swears by 5,000 mile intervals with a quality conventional, and he's got a million miles on his old 12-valve to prove it. That got me thinking, maybe all these synthetic marketers are just selling fear. I've been following that 10k rule for years, but now I'm wondering if I've been doing more harm than good. Anyone else get told something similar by an old timer that made you question everything?

27

kim_patel89•8d ago

TIL I was torquing injector hold-downs all wrong for like 5 years

Last month I pulled a set of injectors on a 6.7 Cummins and found three of them loose just by hand. Turns out I'd been using a dry torque value the whole time instead of accounting for oil on the threads, and a guy at the Cummins shop in Phoenix set me straight. Anyone else figure out a simple mistake way later than they should have?

25

andrew_miller90•8d ago

TIL a $10 fuel filter swap saved me a $1200 injector job

Been seeing a lot of guys in my shop ignore the water separator drain on their Cummins ISX and then blame the CP4 pump when things go south. I pulled a filter off a 2020 Pete last week that looked like someone poured a soda in the tank, brown sludge all through it. How often do y'all actually crack the drain petcock on yours?

8

blake_black47•8d ago

Just realized my timing was off by 2 degrees on a 6.7 Cummins

I was chasing a rough idle on a 2015 Ram 2500 last month, swapped injectors, checked fuel pressure, the whole nine yards. Nothing fixed it. Then I got to talking with an old timer at a parts counter up in Boise, and he asked if I checked the injection timing. I had not even thought about it because the truck ran fine at highway speed. Turns out I was 2 degrees retarded on the cam sensor adjustment. Pulled the gear housing cover, re-set the sensor gap, and it idled smooth as butter. Made me wonder how many other jobs I have overcomplicated because I skipped the basic checks first. Has anyone else spent a ton of time on the wrong fix just to find out it was something simple like timing or a sensor gap?

33

cameron426•9d ago

Blew a coolant hose on I-75 last Tuesday and lost 4 hours of drive time

Was hauling a load of lumber from Atlanta to Macon when that lower rad hose split at the crimp, has anyone else had trouble with Gates hoses failing on newer Cummins engines?

26

andrew778•9d ago

Just found out my shop compressor was running 40% over capacity for 2 years

I was checking the serial numbers on my old Quincy compressor last week and looked up the manual online. Turns out the pressure switch was set to 175 psi when the tank is only rated for 125 psi. How often do you guys actually verify your compressor specs against the tank rating?

16

harper_owens•9d ago

Broke down between buying a used Snap-On scanner or a cheaper generic one for a 6.7 Powerstroke

I went with the cheap one to save $400 and now I can't read half the live data on my 2015 Ford and I'm wondering if anyone else has gone cheap on diagnostic tools and ended up paying more later?

16

paulw63•11d ago

Got burned by a cheap reman injector on a 6.0 last week

I tried saving 50 bucks on a reman injector from a no-name parts place in Phoenix. Put it in a 2006 F-350 on Tuesday, and by Thursday she was knocking like a box of rocks. Pulled it out and found the plunger was already scored up inside. Has anyone else stopped skimping on injectors or do you still roll the dice?

10

diana_king•12d ago

Watched a kid fresh out of school rebuild a PACCAR MX-13 in 4 hours flat last week

He used nothing but a torque wrench and a digital caliper, no impact guns or pry bars, and it fired up first try with zero leaks. How did you learn to work clean like that, or were you just thrown into the deep end like the rest of us?

22

kelly.daniel•13d ago

Old timer at Thompson's shop changed how I check injectors

Guy named Hank, been turning wrenches since the 70s, saw me replacing a set of injectors on a Detroit 60 and said 'kid, you're wasting time pulling them blind'. He showed me to run a compression test first, even if it stumbles, then isolation test each cylinder with a temp gun before ordering parts. Saved me 300 bucks on a job last month - has anyone else had an old school tip that actually works better than the book says?

6

evan_jenkins•13d ago

Old timer at the shop set me straight on injector timing

Had a guy tell me I was wasting time with the dial indicator method on a 5.9 Cummins. He showed me the line bore trick with a straight edge and feeler gauges and I cut my timing job from 3 hours to 45 minutes. Anybody else run into shortcuts that actually work better than book specs?

10

williams90•16d ago

Changed my mind about using air tools for lug nuts after a shop incident

I used to be that guy who always used an impact gun for everything, including tightening lug nuts down on semis. Thought I was saving time and that my torque wrench was just for show. Then last month at the shop on I-85 in Charlotte, a buddy of mine had a wheel separate from a Pete going 55 on the highway. The hub threads were stripped clean from years of impacts being slammed on. That sound of aluminum grinding against concrete stuck in my head. Now I always hand-start with a ratchet and finish with a torque wrench, even if it adds five minutes per wheel. Has anyone else seen what overtightening does to wheel studs over time?

28

veramiller•16d ago

Just found out some injectors are out of spec from the factory

I was reading through some Cummins technical bulletins last night and stumbled on a stat that blew my mind. Over at the shop in Racine, they found that nearly 1 in 12 reman injectors had a flow rate variance of more than 5%. That's enough to cause a rough idle and make your fuel mileage tank. Has anyone else tested injectors straight out of the box and found them off?

3

jordanl82•17d ago

Called BS on a buddy's 'ATF in the diesel fuel' story until I tried it on my old 7.3

My buddy Rick swore up and down that adding a quart of automatic transmission fluid to a full tank would clean out the injectors on my 7.3 Powerstroke. I laughed at him for like ten minutes, figured it was some old wives tale. But last month I was chasing a rough idle that wouldn't go away with normal injector cleaner. Threw in some ATF at a Pilot in Knoxville, ran it hard on the highway for an hour, and the idle smoothed right out by the next morning. Has anyone else actually had this work or was it just a coincidence?

21

evab52•18d ago

TIL some repair shops are charging $200 just to hook up a diagnostic computer

Stopped by a shop near my place in Austin last week to ask about a check engine light on my old Freightliner, and the guy told me it's $200 just to plug in. I get charging for time, but that seems like a lot for something that takes 5 minutes. Has anyone else run into shops doing this?

10

tylermurray•18d ago

Saw a guy trying to torque head bolts with a ratchet yesterday

I was helping a buddy swap a 6.7 Powerstroke at his shop near Akron and this new guy walks in, claims he's been turning wrenches for 10 years. He was cranking down on those bolts using just a 3/8 ratchet and a prayer, no torque wrench in sight. How many of you have seen someone skip the torque specs and just send it?

6

charles678•18d ago

Just found out most of us are using the wrong oil filters

I was reading through some old Cummins bulletins last night and found a stat that blew my mind... over 40% of engine failures in medium-duty trucks are linked to cheap aftermarket filters. The bulletin specifically called out Fram and some no-name brands for not holding pressure right. I double checked my last order and sure enough I had three of them sitting on the shelf. Has anyone else run into issues with off-brand filters on a 6.7 or a DT466?

20

gavinp44•19d ago

Old timer told me to stop using impact guns on injector hold-down bolts

I was at a shop in Tulsa last month and this retired guy watched me swap injectors on a 6.7 Powerstroke. He said I was going to crack a bore if I kept zapping those bolts with my impact. I argued back at first but then tried his way using a torque wrench set to 28 ft-lbs. The truck came back quieter and no more stiction issues. Has anyone else made that switch and seen better reliability?

6

sanchez.mary•19d ago

That old timer who told me to never trust a reman injector without swapping the copper washers first

I blew a head gasket on a 2015 Cummins ISL last spring because I skimped on those $8 washers (thought I knew better, which is always a mistake) and now I replace them every single time without question, anyone else have a cheap part cost them big?

15

xena_kim•20d ago

I walked into a fleet shop last month and counted 12 empty bays

Went to check on a buddy at a big fleet yard in Phoenix and noticed half the bays were empty. They had 12 mechanic spots but only 4 guys working. Shop foreman told me they've been trying to hire for 8 months and can't keep anyone past 3 weeks. He said the starting pay is $28 an hour but the new guys can't handle the heat or the pressure. Made me wonder if the labor shortage is worse than I thought. Anyone else seeing empty bays at shops in their area?