My DPF or regen warning is on — what should I do?

Don't ignore it. The diesel particulate filter cleans itself through regeneration cycles, and repeatedly interrupting those cycles — lots of short trips or shutting down mid-regen — clogs the filter until it needs forced regeneration or replacement. If the warning stays on, have it checked soon. Call or text 573-378-7300.

Diesel Repair | Auto Tech Services

Q: How often should a diesel get an oil change?

It depends on how the truck is used. A diesel that tows, hauls, or idles a lot falls under the manufacturer's severe-duty schedule, which calls for shorter intervals than the normal schedule. Auto Tech Services in Versailles, MO checks your oil condition as part of a free photo-based digital vehicle inspection with every visit and recommends an interval that fits how you actually use the truck.

Q: What does black, white, or blue smoke from a diesel mean?

Black smoke usually points to excess fuel or restricted air — injector, turbo, or air filter issues. White smoke suggests unburned fuel or coolant entering the cylinders. Blue smoke means the engine is burning oil. Each one points to a different system, so a proper diagnosis matters before any parts are replaced.

Q: Do you work on diesel pickups like Powerstroke, Cummins, and Duramax?

Yes — Auto Tech Services works on light and medium-duty diesel trucks, including the common Powerstroke, Cummins, and Duramax pickups, for both repair and routine maintenance.

Diesel Service & Repair — Trucks, Work Rigs, and Everything In Between

Diesel engines are built to last — but they have their own set of service needs, and they need a shop that understands them. At Auto Tech Services, we work on diesel-powered trucks and vehicles regularly. Whether it's a routine oil service or a fuel system issue bringing you down, we have the tools and experience to handle it.

We serve farmers, contractors, and everyday diesel truck owners in Versailles and the surrounding area. When your work truck isn't running, your day doesn't run either. We get that, and we work to get you back on the road as quickly as possible.

Signs Your Diesel Needs Service

Hard starting, especially in cold weather
Loss of power or sluggish acceleration
Excessive black, white, or blue smoke from the exhaust
Fuel economy has dropped noticeably
Rough idle or engine knocking
Check engine light or DPF/DEF warning lights on
Unusual fuel smell or visible leaks

Diesel Services We Provide

Diesel oil and filter service
Fuel filter replacement (primary and secondary)
Fuel injector diagnosis and service
Glow plug inspection and replacement
Turbocharger inspection and diagnosis
DEF (diesel exhaust fluid) system service
DPF (diesel particulate filter) diagnostics
EGR system diagnosis and cleaning
Diesel engine diagnostics and check engine light diagnosis
Cooling system service

Ford Super Duty diesel truck on the lift for repair at Auto Tech Services in Versailles, MO

Technician installing a new diesel engine at Auto Tech Services

Our Approach

Diesel diagnostics require specific equipment and know-how. We don't guess at fuel system problems — we run the proper tests, check injector balance rates, monitor boost pressure, and verify the issue before recommending parts. That means you're not paying for repairs you don't need.

Diesel Work Is Different

A modern diesel isn't just a gas engine that burns different fuel. High-pressure common rail injection systems run at pressures a gas engine never sees, and a single failing injector can wash out a cylinder if it's ignored. Add glow plugs for cold starts, a turbocharger feeding boost under load, and the EGR and DPF emissions systems layered on top, and you've got an engine that needs different tooling and different experience to diagnose correctly. Guessing at diesel parts gets expensive fast — injectors and turbos aren't cheap, so we verify before we recommend anything.

And if a diesel engine is genuinely worn out or damaged beyond economical repair, we'll tell you that straight, too. As a Jasper remanufactured engines installer, we can put a like-new diesel engine under the hood with a 3-year/36,000-mile nationwide warranty. For gas engines and general engine work, see our engine repair page.

Trucks That Work for a Living

Around Morgan County, diesel trucks aren't a lifestyle choice — they're how work gets done. Farm trucks hauling feed and equipment, contractors' work trucks loaded down five days a week, and trucks towing boats in and out of the Lake of the Ozarks all summer. We see them daily from Versailles, Eldon, Stover, Barnett, Laurie, Gravois Mills, Sunrise Beach, and the surrounding area.

Trucks that tow and haul live a harder life than the odometer suggests, which means preventive maintenance matters even more — fluids break down faster under load, and small problems become breakdowns at the worst possible time. Every visit includes a free photo-based digital vehicle inspection so you can see the condition of your truck for yourself. And if a repair takes more than a day, ask about our loaner cars so you're not stuck without a way to get around.

Diesel Repair FAQs

How often should a diesel get an oil change?

It depends on the duty cycle. A diesel that tows, hauls, or idles a lot falls under the manufacturer's severe-duty schedule — shorter intervals than the normal schedule printed in the owner's manual. Rather than quote one number for every truck, we check your oil condition as part of the free digital vehicle inspection at every visit and recommend an interval that fits how you actually use the truck.

Why is my diesel hard to start in cold weather?

The usual suspects are worn glow plugs, weak batteries, or fuel that's started to gel in the cold. Diesels rely on compression heat to fire, so anything that slows the cranking speed or cools the cylinders makes cold mornings rough. We test glow plugs, load-test the batteries, and check the fuel system to find the actual cause instead of throwing parts at it. Call or text 573-378-7300 and we'll get it sorted before winter does it for you.

What does black, white, or blue smoke from a diesel mean?

Black smoke usually means too much fuel or not enough air — think injector, turbo, or air filter problems. White smoke points to unburned fuel or coolant getting into the cylinders. Blue smoke means the engine is burning oil. Each color points to a different system, so a proper diagnosis matters before anyone starts replacing parts.

Do you work on diesel pickups like Powerstroke, Cummins, and Duramax?

Yes — we work on light and medium-duty diesel trucks, including the Powerstroke, Cummins, and Duramax pickups that are everywhere around here. Repairs and routine maintenance alike. If the problem turns out to be electrical rather than mechanical, our advanced electrical diagnosis covers that side too.

My DPF/regen warning is on — what should I do?

Don't ignore it. The diesel particulate filter cleans itself through regeneration cycles, and repeatedly interrupting those cycles — lots of short trips, or shutting the truck down mid-regen — clogs the filter until it needs a forced regeneration or replacement. If the light stays on or the truck goes into reduced power, get it checked soon. Call or text 573-378-7300 and we'll quote the diagnosis before we start.

Diesel truck giving you trouble?

We'll diagnose it and get you a straight answer.

573-378-7300 Send a Questionnaire