Diesel Engine Repair

Engine work for trucks, commercial vehicles, and trailers

Modern Diesel keeps your vehicles moving with experienced technicians performing critical maintenance and repair. We service medium- and heavy-duty commercial vehicles, trucks of all sizes, and trailers — with the diagnostics and quality parts to get it right the first time.

What we work on

• Power Stroke — fuel systems, regeneration, diagnostics, and emissions
• Cummins — fuel systems, engine repairs, emissions, and diagnostics
• Duramax — injectors, CP4 fuel systems, and emissions work
• Air brakes on semis and heavy-duty trucks
• Preventative and fleet maintenance to keep engines healthy

Engines and makes we cover

Beyond the platforms above we work on Detroit Diesel (DD13/DD15 and Series 60), Mercedes-Benz diesel (OM642/OM651), Isuzu and Hino medium-duty engines, and the off-road diesel in heavy equipment. Specialty platforms too — HMMWV and military vehicles, Unimog, and EarthRoamer & TruckHouse expedition rigs.

When it is not the engine

Plenty of "engine" complaints turn out to be something feeding it. Overheating is usually a cooling system problem before it is an engine one, and a truck that is down right now is a truck-down conversation. See service options for how one-off repairs and fleet programs fit together.

Diagnostics first, not guesswork

A rough-running or hard-starting diesel can have a dozen causes. We use current diagnostic tools to pinpoint the actual fault, then repair it with quality parts — so you’re not paying to swap parts that didn’t need swapping.

Warranty coverage is set with your service advisor at the time of service.

Why Modern Diesel

A Christian, veteran-owned shop serving the Greater Austin Area (Travis, Bastrop, Williamson, Hays) since 2015. Honest work, fast turnarounds, and technicians who take pride in every job. Call to get your engine scheduled.

Common questions

What are the signs a diesel engine needs repair?

The common ones are hard starting, rough idle or misfire, a noticeable loss of power, blue or black smoke, knocking or new noises, oil or coolant loss, and a check-engine light that keeps coming back. Any of these are worth diagnosing early — on a diesel, a small fuel or emissions fault left alone usually turns into a much larger repair.

Do you work on Power Stroke and Cummins engines?

Yes — Power Stroke and Cummins are our bread and butter, covering fuel systems, regeneration and emissions, diagnostics, and engine repair. We also service light-, medium-, and heavy-duty diesel of other makes, plus air brakes on semis and heavy trucks.

Do you rebuild diesel engines, or only repair them?

Both. We handle everything from a single component repair to a full rebuild. Which one makes sense depends on what the diagnosis turns up and on the age, mileage, and condition of the rest of the truck — we lay out the options and what each one buys you before any work starts.

How much does diesel engine repair cost in Austin?

It depends entirely on what is actually wrong, so we diagnose first rather than quote blind. Once we know the fault, you get an estimate to approve before we start the work — and we use diagnostics rather than swapping parts, so you are not paying for components that did not need replacing.