Diesel Truck Mechanic Shops in Guelph, ON

Find trusted diesel truck mechanic services in Guelph. Compare prices, read reviews, and book online.

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Century Truck And Trailer Repair
Guelph • ≈ 3 km
CE
15 Winer Rd, Guelph, ON N0B 2J0, Canada, Guelph
★ 5.0
30 Google reviews
Response ≈ 20 min $ • Quotes free
Diesel Truck Mechanic Truck MechanicTruck & Heavy Duty
📞 (519) 836-0091 Free quote • Verified
Vtech Diesel and DPF cleaning
Guelph • ≈ 7 km
VT
4922 7 Line, Guelph/Eramosa, ON N0B 2K0, Canada, Guelph
★ 5.0
3 Google reviews
Response ≈ 28 min $$$ • Quotes free
Diesel Truck Mechanic
📞 (416) 270-3311 Free quote • Verified
Smoke Tech Mobile Diesel Emission Testing
Guelph • ≈ 3 km
SM
847 Stone Rd E, Guelph, ON N1L 1B8, Canada, Guelph
★ 4.9
14 Google reviews
Response ≈ 34 min $ • Quotes free
Diesel Truck Mechanic Fuel System
📞 (519) 821-9800 Free quote • Verified
Michael's Mobile Truck & Trailer Repairs Inc.
Guelph • ≈ 4 km
MI
7426 Wellington County Rd 34, Guelph, ON N0B 2J0, Canada, Guelph
★ 4.5
46 Google reviews
Response ≈ 40 min $ • Quotes free
Diesel Truck Mechanic Truck Mechanic
📞 (519) 780-2710 Free quote • Verified
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Verified Reviews for Diesel Truck Mechanic
★ ★ ★ ★ ★

“Would recommend Smoke Tech to all that need a mobile e-test done on their commercial vehicles.”

Robert Le Cam • Diesel Truck Mechanic at Smoke Tech Mobile Diesel Emission Testing, Guelph
★ ★ ★ ★ ★

“I've used smoke tech for years! Kirk is a very polite business owner and his employee Ian has a great personality as well. I call for an appointment and often get same day service. They are able to perform their service in driveways, parking lots ect. which is very convenient!”

Jordan Chartrand • Diesel Truck Mechanic at Smoke Tech Mobile Diesel Emission Testing, Guelph
★ ★ ★ ★ ★

“I run a business where our trucks and trailers need to be on the road every single day, downtime simply isn’t an option. When one of our units went down, we were stuck and losing money fast. After calling several repair shops and getting timelines of a week or more, I was referred to Michaels Mobile Truck and Trailer Repairs and I’m very glad I was.

From the first call, Michael was responsive, knowledgeable, and understood exactly what we needed. He tracked down all the necessary parts the same day and committed to being on-site the following morning.

True to his word, he showed up on time and completely exceeded our expectations. Within just a couple hours, he had removed the damaged components, installed the new parts, and had us fully operational again.

He quite literally saved us thousands of dollars and got us back on the road within 24 hours, something no other shop I contacted could even come close to.

I can’t say enough good things about Michael and the level of service he provides. Going forward, he’ll be our go-to for maintaining our entire fleet.”

Chris Heartfield • Diesel Truck Mechanic at Michael's Mobile Truck & Trailer Repairs Inc., Guelph
★ ★ ★ ★ ★

“Got a blow out on the highway and limped my truck here to put on my spare tire. I was in and out in under an hour”

P L • Diesel Truck Mechanic at Century Truck And Trailer Repair, Guelph
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Find a Best Diesel Truck Mechanic in Guelph, ON

Boommar lists 4 verified mechanics in Guelph. Compare real reviews, response times, pricing bands, and open bays — then book online.

Common Diesel Truck Issues

Contaminated diesel fuel or clogged fuel filters restricting flow
Failing fuel injectors or high-pressure fuel pumps (HPFP) losing rail pressure
Clogged EGR valves and cracked EGR coolers causing overheating and coolant loss
Turbocharger bearing failure, sticking variable-geometry vanes, or boost leaks
Glow plug or intake heater malfunctions preventing cold-weather starting
Diesel Particulate Filter (DPF) clogging from excessive idling or short trips

When to Book a Diesel Mechanic

Hard starting or extended cranking, especially in cold weather
Excessive black smoke (rich running), white smoke (coolant leak), or blue smoke (oil burning) from the exhaust
Distinct metallic "knocking" or "clatter" sound indicating injector or bearing failure
Check Engine light, Water in Fuel warning, or emission system derate mode
Significantly reduced towing power, turbo lag, or sluggish acceleration
Frequent forced DPF regeneration cycles or "Exhaust Filter Full" warnings on the dash

Diesel Truck Mechanic Services Available

Diesel Fuel System Repair

Injector replacement, high-pressure fuel pump rebuilds, and rail pressure testing

Turbocharger Diagnostics & Replacement

Boost leak testing, VGT actuator repair, and full turbo replacement

EGR/DPF/DEF Emission System Service

EGR cooler replacement, DPF cleaning/baking, and DEF injector diagnostics

Glow Plug & Cold Start Service

Testing, extraction of seized glow plugs, and intake heater repair

Diesel Engine Diagnostics

Factory-level scanning for Cummins, Duramax, Power Stroke, and Detroit engines

Diesel Performance Tuning

ECM calibration, exhaust upgrades, and intake system optimization

Diesel Truck Mechanic Tips

Always purchase diesel fuel from high-volume, reputable stations to minimize contamination risk
Drain the water separator at every oil change and immediately if the Water in Fuel light illuminates
Use a high-quality winter anti-gel additive when temperatures consistently drop below -15°C
Avoid excessive idling—it prevents the DPF from reaching regeneration temperature and causes clogging
Let the turbo cool down by idling for 30-60 seconds before shutting off the engine after heavy towing
Follow the severe-duty oil change interval if you tow, haul, or drive in extreme temperatures regularly

Frequently Asked Questions

Are diesel truck repairs more expensive than gas engine repairs in Guelph? +
Generally, yes. Diesel engines operate at much higher pressures and tolerances than gasoline engines. Components like fuel injectors ($300-$600 each), high-pressure fuel pumps ($1,500-$3,000), and turbochargers ($1,500-$3,500) are significantly more expensive. Diesel-specific diagnostic tools and specialized labor also contribute to higher repair costs.
How much does a diesel fuel injector replacement cost in Guelph? +
A single diesel injector replacement costs $500-$1,000 including parts and labor. Replacing all injectors on a common 6-cylinder diesel (Cummins 6.7L, Duramax 6.6L, or Power Stroke 6.7L) typically runs $3,000-$6,000+. It's often recommended to replace all injectors at once to avoid repeat labor costs.
What does it mean when my diesel truck goes into derate or limp mode? +
Derate mode is the engine's ECM intentionally reducing power to protect itself from further damage, usually triggered by emission system faults (DPF, DEF, EGR), overheating, or low oil pressure. You should drive only to the nearest safe repair facility at reduced speed. Ignoring derate can lead to a complete engine shutdown.
How often should I service my diesel truck's DPF system? +
Most diesel DPF systems require a professional cleaning (ash removal) every 150,000-300,000 km, depending on driving conditions. Trucks driven primarily in city stop-and-go traffic or at idle may need it sooner. A DPF cleaning costs $300-$600 and is far cheaper than a replacement filter ($2,000-$5,000+).