Engine & Performance Upgrades in Bethany, MO

Maximize Power. Extend Engine Life. Run Stronger.

When it comes to hauling loads and meeting deadlines, your truck’s engine performance matters. At Guernsey’s Truck Trailer and Tire Service, we provide professional engine upgrades and diesel performance enhancements for heavy-duty trucks, semi trucks, and commercial vehicles. Based in Bethany, MO and serving a 250-mile radius, we help truckers boost power, improve efficiency, and extend the life of their engines.


Whether you're looking for improved fuel economy, better pulling power, or a complete rebuild, our experienced team is here to deliver lasting results.

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A man is working on a truck in a garage.

Our Engine Services

We handle all aspects of diesel engine care, from regular maintenance to full performance tuning. Every service is backed by 20+ years of hands-on experience and a commitment to quality.

Engine Repair and Rebuild Services:

  • Full engine diagnostics and code reading
  • Head gasket replacements and resealing
  • Valve and cylinder work
  • Turbocharger repairs and replacements
  • Fuel injector testing and replacement
  • Engine rebuilds for all major manufacturers

Performance Upgrades Include:

  • Diesel tuning and ECM adjustments
  • Fuel system improvements
  • High-flow intake and exhaust upgrades
  • Cooling system enhancements
  • Torque and horsepower optimization

We only use reliable, road-tested components that meet or exceed OEM standards to ensure long-term durability and safety.

Engine Repair and Rebuild Services:

  • Full engine diagnostics and code reading
  • Head gasket replacements and resealing
  • Valve and cylinder work
  • Turbocharger repairs and replacements
  • Fuel injector testing and replacement
  • Engine rebuilds for all major manufacturers

Performance Upgrades Include:

  • Diesel tuning and ECM adjustments
  • Fuel system improvements
  • High-flow intake and exhaust upgrades
  • Cooling system enhancements
  • Torque and horsepower optimization

We only use reliable, road-tested components that meet or exceed OEM standards to ensure long-term durability and safety.

Serving Long-Haul and Local Truckers

Whether you’re a regional hauler or an over-the-road driver, performance matters. We work with single operators, small fleets, and commercial managers to deliver cost-effective upgrades that make your truck work smarter and harder.

Common Signs You Need Engine Service

  • Loss of power on climbs or under load
  • Poor fuel economy despite light loads
  • White, black, or blue exhaust smoke
  • Hard starts, misfiring, or rough idling
  • Oil or coolant leaks near the engine block


If your truck is showing any of these symptoms, it’s time to bring it in for a diagnostic. Early detection can prevent major breakdowns and costly downtime.

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24/7 Expert Repairs

Around-the-clock service Monday–Friday for trucks, trailers & heavy-duty equipment — minimizing your downtime, maximizing your uptime.

Why Guernsey’s for Truck and Trailer Repair?

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20+ years of industry experience

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Rapid diagnostics and in-stock parts

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24-hour service Monday through Friday

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Skilled in both truck and trailer systems

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Transparent pricing and clear communication

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Located just off major routes for easy access

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FAQs About Truck and Trailer Repair

  • What kinds of trailers do you repair?

    We work on dry vans, flatbeds, refrigerated trailers, and more. From brakes to landing gear, we can handle it.


  • How quickly can you diagnose a problem?

    In most cases, we begin diagnostics the same day. Our experienced techs work quickly to identify and resolve the issue.

  • Do you offer emergency roadside repair?

    Yes. Our mobile unit operates with no mileage restrictions and can reach you within our 250-mile service range.

  • Can you handle welding and frame repairs?

    Absolutely. We offer on-site and in-shop welding for structural repairs to both trucks and trailers.

Schedule Repair or Request Mobile Service

Need truck or trailer repairs now? Contact Guernsey’s Truck Trailer and Tire Service for fast, reliable service you can trust.


Phone: (660) 373-2178

Email: guernseytruck@gmail.com

Location: 25773 West US Route 69, Bethany, MO 64424


We’re ready to keep your rig moving.

Contact Us