Automotive & Diesel

Customer's 2018 Silverado kills a brand-new battery in about four days sitting. Alternator tests fine. How do I actually run a parasitic draw test on this thing and what number am I looking for?

Slow-crank complaint, battery load-tests good, starter draws about normal amperage. I want to do voltage-drop tests on the starter circuit. Where do I put the leads and what drops are acceptable?

Doing a brake job on a Camry, pads are down to nothing and the rotors are grooved. How do I decide whether I can turn the rotors or have to replace them?

Guy brings in a trailer with tires that have deep tread but look a little cracked. How do I tell how old the tires are and when do I tell him they're done?

Doing a brake flush on a 2015 F-150 that calls for DOT 3. I've only got DOT 4 and a bottle of DOT 5 on the shelf. Can I use either one?

Got a Honda with a steady misfire on #3, coils and plugs swapped, injector swapped, still on #3. When do I go to a compression test versus a leak-down, and what results tell me it's mechanical?

Chrysler minivan with a U0100 lost communication with ECM and half the modules on the network dropping out intermittently. How do I check the high-speed CAN bus with a meter before I start pulling connectors?

New tech mounting wheels back on cars. What's the right way to torque lug nuts and do I really need to have the customer come back to re-torque?

Replacing a condenser on a 2012 Accord with R-134a. After I get it back together, how long do I pull vacuum, and how do I know how much refrigerant to put in?

We've been an R-134a shop forever and now the 2020+ stuff coming in is R-1234yf. What's actually different about servicing it besides the fittings?

Customer wants me to put 5W-30 conventional in his 2021 Toyota because 'that's what he's always run.' The cap says 0W-16. Does it matter?

Fleet customer with 2019 Ram 6.7 Cummins has a DEF quality warning and derate countdown. He swears he just filled it. What do I check and what are the rules on the DEF itself?

Peterbilt with a Paccar MX-13 keeps coming back with DPF high soot load codes and the driver says the forced regens only help for a week. What's the actual diagnostic path before I sell him a DPF cleaning?

2006 Duramax LBZ hard-starts after sitting overnight but fires right up if it's been shut off for less than an hour. Runs fine once it's going. Where do I start?

I'm about to replace the inverter coolant pump on a 2017 Prius and the high-voltage cables run right over it. What's the exact safety sequence before I touch anything orange?

Doing the timing belt on a 2008 Honda Odyssey J35. What else goes with it, and how do I make sure I haven't screwed up the timing before I put the covers back on?

Subaru 2.5 with coolant loss, no visible leak, white smoke sometimes and the overflow bottle bubbles. How do I confirm a head gasket without tearing it down?

Customer's Escape has a growl that gets louder with speed, and it changes when she swerves left or right. She's been told 'tires' twice. How do I nail down a wheel bearing versus tires?

2014 Malibu with a P0304 and a flashing check engine light. Boss said 'swap it and see.' Swap what, in what order, and why is the light flashing?

6.0 Powerstroke... actually no, a 2011 Cummins ISX15 with low power, no codes, and rail pressure that sags under load. How do I test the injectors for return flow and what's the shop-air side of that?

I just started at a small shop and the owner wants me to start doing A/C recharges. Do I need some kind of license to buy refrigerant and work on car A/C?

DOT roadside guy wrote up one of our customer's dump trucks for tires. What are the actual tread depth minimums for a commercial truck, front versus rear?

Customer with a 2015 Ram 2500 diesel wants us to do a 'delete' — DPF, EGR, and a tune. We're in Jacksonville and Florida doesn't do emissions testing, so is it legal?

Opening a two-bay shop in Clay County. What are the rules on my used oil, old filters, and antifreeze — can I just have the guy with the truck take it?

In Florida, does a customer really have to sign a written estimate before I touch the car? Where's the line, and what if the job grows once I'm in there?

Evaporator's shot on a 2009 Civic and the customer's just going to scrap the car. Can I just crack the line and let the R-134a out since the car's going to the crusher anyway?

Doing an annual on a tandem dump with Type 30 brake chambers. What's the pushrod stroke limit I'm checking against, and how do I actually measure it?

2016 Altima with 110k miles, P0420, and the OE cat is $1,800. Customer wants the $250 universal converter off the internet. We're in Florida. What are the rules on installing an aftermarket converter?

Apprentice is diagnosing a charging problem on a 2012 Tahoe. Battery's charged, truck's running at idle, and he says 'I'm going to pull the negative cable off — if it keeps running the alternator's good.' What's wrong with that?

Tire guy in the next bay mounts four wheels on a Tacoma, hits every lug with a 1/2-inch impact until it stops, drops the truck, and sends it. Customer's back in two weeks with a steering wheel shimmy under braking. What happened?

Customer limps in with the temp gauge pegged. The lube tech pops the hood, grabs a rag, and starts twisting off the radiator cap to 'see if it's got coolant.' What's about to happen?

Head gasket job on a 2007 Chevy 5.3 LS. Tech cleans up the old head bolts on the wire wheel, oils the threads, and torques them to 22 ft-lb then 90 degrees like the book says. Where's this going wrong?

Fuel filter service on a 2012 Duramax LML. Tech spins on the new filter, hits the key, cranks it 20 seconds, cranks again, third time it fires and runs. He says it's good. Why might this truck be back on a hook in a month?

There's a diesel mist and a smell on a running 2015 Ram 6.7 Cummins. Tech is running his bare hand along the high-pressure lines from the rail to the injectors to feel for where it's spraying. Stop him?

Camry Hybrid comes in with no A/C, compressor's dead. Tech pulls the electric compressor, installs a new one, and tops the system with the same PAG 46 he uses on everything before charging. Anything wrong?

Tech is doing an A/C 'recharge' on a 2010 Impala: he screws a 12-oz can with sealer onto the low side, runs the engine, watches the low-side gauge until it reads 35 psi, and calls it done. What's he done wrong?

Restoration guy brings in a 1999 Suburban with ABS and says he 'upgraded' it with DOT 5 silicone fluid for long-term storage. Now the pedal is spongy and the ABS is chattering at low speed. What's going on?

Fleet has a 2008 International with a DT466 and a wet-sleeve design. Shop refills the cooling system after a water pump with 50/50 green conventional automotive antifreeze off the shelf, no additives. Two years later they're pulling the engine for coolant in the oil. Connect the dots.

Tech gets a Corolla with P0420, reads the code, sells the customer a new converter, installs it, clears the code, and the light comes back in 400 miles. He wants to warranty the converter. What did he miss?

Tech is replacing a clockspring on a 2013 Accord. He disconnects the battery negative, immediately unbolts the airbag, sets it face-down on the bench, and starts probing the yellow connector with a test light to check continuity. Rank the mistakes.