Derate?Won't start? We fix it.
Diesel engine diagnostics & repair across Indianapolis — Cummins, Detroit, PACCAR, Volvo, Mack & Cat. Shop or mobile.
Road X repairs diesel engines for semis and commercial trucks at our Indianapolis shop on Massachusetts Ave and by mobile unit anywhere inside the I-465 loop and along I-70, I-65 and I-69. Whether it's a check engine light at a truck stop or an in-frame that needs the shop, we run it. Call (317) 551-5253 and a diesel tech picks up — not a call center.
Real engines. Not "all makes."
Cummins, Detroit, PACCAR, Volvo, Mack and Cat. Here's what we see fail most on each.
EGR cooler leaks, injector cup failure, cam and rocker wear on high-mile units.
Turbo actuator faults, DEF doser clogs, one-box aftertreatment codes.
EGR valve sticking, coolant loss into the EGR cooler, rear main leaks.
Injector cup coolant leaks, cam sensor faults, VGT actuator issues.
Same D-family core as Volvo — EGR, injector cups, DEF dosing.
Turbo actuator, EGR cooler, 7th injector on medium-duty and school buses.
Legacy pre-emission — head gaskets, injector cups, twin-turbo work on ACERT.
What's it doing?
Derate & check engine codes
Yellow light with 5 mph max means the ECM has put you in derate. Usually DEF quality, SCR efficiency, or an aftertreatment sensor. We pull codes with Cummins Insite, DDDL or JPRO, force a regen if that clears it, and swap the failed sensor if it doesn't. If the code is throttle- or fuel-side, we chase pressure and rail values before touching parts.
Injector failure
Rough idle, white smoke, or a knock that changes with load. Sometimes a fuel-in-oil condition on Cummins X15. We cylinder-cut with the laptop to isolate the bad hole, then pull valve covers and replace the injector, cup, or o-ring set. Reprogram trim codes before start-up.
Turbo problems
Loss of power up a grade, black smoke, or a boost fault code. Most late-model turbos are variable-geometry with an electric actuator that seizes or throws position errors. We test actuator sweep, check the vanes for carbon, and replace the actuator or the full cartridge. On older twin-turbos we chase oil-return restriction first.
Coolant loss & overheating
Coolant showing up in the DEF tank on a Volvo D13, or the surge tank going empty every 500 miles. On MX-13 and D13 that's usually the EGR cooler or injector cup seals. On Cummins it can be head gasket or a cracked EGR cooler. We pressure-test cold, then hot with a combustion-gas test on the surge tank.
Oil leaks
Puddle under the bell housing usually means rear main. Front-side leaks are often the front cover, timing gasket, or oil cooler. We clean the engine, dye-check with UV, and drive it to find the actual source before we start pulling parts.
Hard start & no-start
Cranks but won't fire — check fuel rail pressure and injector return flow first. Doesn't crank — battery bank, cable ends, and starter draw. Cold-morning no-starts on ISX and DD15 are often the fuel prime pump, block heater plug, or bad glow relay. We test before we replace.
DPF & regen faults
SPN 3251 or 3720, forced regen won't complete, or the truck goes into derate every 300 miles. Could be a clogged DPF, failed differential pressure sensor, DEF quality below 32.5%, or a hairline crack in an aftertreatment tube. We run a parked regen, backpressure-test the DPF, and pull it for bake or replacement if it's over 100 grams of soot.
Which do you need?
Diagnostics, sensor swaps, injector work on top of the head, forced regens, DEF pump and doser jobs, turbo actuators, coolant hose and fuel line failures. Anything we can do at the wheel or on top of the head, we bring to you. Payment on the invoice before we roll.
In-frames, out-of-frames, head gaskets, oil pan drops, timing gear work, and anything that needs the truck lifted or the engine out. Address is 5301 Massachusetts Ave, Indianapolis, IN 46218. If you can't move it, we'll arrange a wrecker to get it in.
Engine repair across Indianapolis.
We work the I-70/I-65 South Split every week — that's where derates happen when a truck sits in traffic and the DPF loads up. Regular runs to the Mount Comfort corridor for logistics yards, Park 100 and Ameriplex on the west side, the TA on Post Road and the Pilot on Harding Street. Plenty of calls from drivers who limped off an I-465 exit and pulled into a Love's or a Speedway lot.