Southwest Diesel Service Inc. is a diesel truck shop and mobile mechanic based in St. George, Utah. For an RV stuck on the shoulder it comes to you, offering 24/7 mobile roadside repair, and for scheduled work you can bring the rig to its shop on 350 North.
It works on air conditioning, batteries, brakes, engines, oil changes, starters, suspension, transmissions and tune-ups on RVs, along with heavy duty and medium duty trucks and trailers. Beyond roadside fixes, it also does RV inspections, including the kind you want before buying a used rig or for an annual state inspection, and winterizing, where it disconnects, drains and bypasses the systems so the rig sits safely until next season. It serves St. George, Washington, Hurricane, Cedar City, La Verkin, Ivins, Santa Clara, Toquerville and Leeds.
No trip fee, hourly rate or diagnostic fee is published, so ask about the trip fee and what a job will run when you call. Shop hours are Monday through Friday, 8:00am to 5:00pm, but the roadside repair line runs around the clock. The business has been at it for over 30 years, with technicians it says bring "over 60 years combined experience," and it is a CAT and Cummins dealer, authorized to do warranty work on those engines, with an extended warranty offered on overhauled CAT and Cummins engines it repairs.
Google rates it 4.4 stars from 51 reviews.
This is a good fit for a traveler broken down along I-15 in southern Utah who needs someone to come to the roadside, and for an owner nearby who wants a pre-trip inspection or winterizing done by a shop that also handles diesel engine work.
| Based in | Saint George, UtahMobile: comes to the RV |
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| Service area | “we proudly serve St. George and the surrounding communities with expert heavy‑duty and medium‑duty truck, trailer and RV repair.”swdieselservice.com |
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| Trip fee and hourly rate | Not published. Ask on the phone what the trip fee is and whether it includes the first hour. |
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| Hours | Mon-Fri 8:00am-5:00pmswdieselservice.com; takes after-hours and emergency calls |
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| Works on | Air conditioningGeneratorsBatteries and solarChassis, brakes and tiresListed at swdieselservice.com. This is what they list, not a limit; ask about anything else. |
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| Certifications | None named |
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| Listed as | “Air-conditioning Service or Repair; Alternators; Batteries; Brake Repair or Replacement; Belts; Clutches; Exhaust systems; Hitches; Hoses; Radiators; Seal leaks; Transmissions; Air conditioning; Brakes; Engines; Oil changes; Starters; Suspension; Tune-ups” |
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| Time in business | “for over 30 years” |
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| Google rating | 4.4 of 5, 51 reviewsGoogle Maps listing, read October 7, 2026 |
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