Truck Engine Repair in Glasgow, MT
Dependable Engine Repair for Diesel and Heavy Duty Trucks
Your engine is the most important system in your truck — when it fails, so does everything else. At Thompson & Sons Inc. in Glasgow, MT, we specialize in professional engine diagnostics and repair for diesel, commercial, and heavy-duty trucks. Whether your check engine light is on, you’re losing power under load, or you’ve noticed excessive smoke, we’ll get to the root of the issue and fix it right the first time.

We service individual owner-operators, fleet managers, and equipment operators across northeast Montana, offering full-service support for engine problems large and small.
Diesel Engine Repair Services
Our team works on all major diesel platforms, including Cummins, Duramax, Power Stroke, Detroit Diesel, Caterpillar, and International engines. We perform everything from routine tune-ups to full engine rebuilds and replacements.
Engine services include:
Complete engine diagnostics
Cylinder head and gasket repairs
EGR and DPF service
Fuel injector testing and replacement
Turbocharger replacement
Timing components
Water pumps, oil pumps, and cooling system service
Exhaust system repairs
Crankshaft and camshaft inspections
Top-end and bottom-end engine repairs
Whether your truck is misfiring, overheating, or burning oil, we have the experience and equipment to handle the repair efficiently and affordably.
Engine Diagnostics and Troubleshooting
Modern diesel engines rely on advanced sensors and control modules. Our technicians use high-end diagnostic tools to read trouble codes, monitor live engine data, and track down performance issues with precision.

Common engine problems we diagnose:
- Loss of power or torque
- Hard starting or rough idle
- Excessive fuel consumption
- White, black, or blue exhaust smoke
- Knocking or unusual engine noise
- Overheating under load
- Check engine lights
- Regeneration system issues
We don’t rely on guesswork. We’ll diagnose the issue accurately and walk you through your options before any repairs begin.
Mobile Engine Repair Services
If your truck breaks down before you make it to the shop, we offer mobile engine diagnostics and limited repair services on location. Our mobile units are equipped to respond across northeast Montana, helping you avoid costly tows and downtime.
Mobile engine services include:
On-site diagnostics and troubleshooting
Fluid checks and top-offs
Battery and sensor replacement
Hose and belt repair
Cooling system repairs
Fuel delivery and jump starts
For major engine problems, we can help arrange transport to our Glasgow facility for full-service repair.
Engine Rebuilds and Replacements
Sometimes, engine failure is beyond a simple fix. In those cases, Thompson & Sons Inc. offers in-house rebuilds and engine replacement options to get your truck back on the road with long-term reliability.

We offer:
- Partial or full engine rebuilds
- Remanufactured engine installation
- OEM and aftermarket part sourcing
- Complete teardown and cleaning
- Warranty options depending on engine type
We’ll inspect your engine, assess internal damage, and present cost-effective repair or replacement options. Our goal is always to maximize value while restoring performance and durability.
Preventive Engine Maintenance
The best way to avoid engine trouble is regular maintenance. We provide diesel engine maintenance for individual trucks and fleet accounts.

Preventive engine services include:
- Oil and filter changes
- Fuel and air filter replacements
- Cooling system flushes
- Valve adjustments
- Glow plug and sensor testing
- Belt and hose checks
- Emissions system cleaning
Our team tracks service intervals and can set up a routine schedule that fits your business needs. This helps reduce costly downtime and improves fuel economy and performance over the long haul.
Fleet Engine Service
Managing a fleet means keeping trucks on the road and avoiding engine-related failures. We work with commercial fleet clients to provide regular engine inspections, diagnostics, and repairs as part of a full maintenance program.

Fleet benefits include:
Priority scheduling and turnaround
Service history documentation
Scaled maintenance plans
On-site engine checks for large fleets
Discounted labor and bulk pricing
Let us handle the engine work so your drivers can stay focused on the job.
Why Choose Thompson & Sons Inc. for Engine Repair
Truck owners and fleet operators throughout Valley County trust us because we combine expert repair with local service. We’re not a franchise we’re a family run business that values precision, communication, and reliability.
What sets us apart:
Advanced diesel engine knowledge
Clean, organized, and well-equipped shop
Experienced with complex repairs and rebuilds
Transparent estimates and honest timelines
Mobile and in-shop service options
Locally owned and community-driven
Whether it’s your daily hauler or your entire fleet, we’ll help you get every mile out of your engine.
Book Your Engine Repair Today
If your truck is running rough, showing warning signs, or in need of a major repair, don’t wait. Contact Thompson & Sons Inc. to schedule diagnostics, get a repair quote, or request mobile service.
Phone:
(406) 228-4801
Email:
thompsonmandsons@nemont.net
Address: 53997 Highway 2 West, Glasgow, MT 59230
Hours: Monday–Friday, 8 am – 12 pm and 1 pm – 5 pm
We’re here to keep your truck running strong — one repair at a time.