Marcus Reid

Diesel Technician & Senior Contributor

Marcus spent two decades in independent diesel shops before moving into writing, working mostly on Power Stroke, Cummins and Duramax pickups along with the RVs and farm equipment that came through the same bays. At USA Diesel Finder he covers diagnostics, DPF and emissions systems, and the practical side of choosing a shop — what a fair estimate looks like, which symptoms can wait, and which ones can't. His goal is to give owners enough context to have a confident conversation with their mechanic.

Articles by Marcus Reid

How to Compare Diesel Repair Quotes Without Getting Burned
Cost Guides
6 min read

How to Compare Diesel Repair Quotes Without Getting Burned

Diesel repair quotes for the same job can swing by hundreds or even thousands of dollars. Learn what belongs in a fair quote, which red flags signal a bad shop, and how to compare parts, labor, and warranty terms side by side.

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Cost Guides
7 min read

Mobile Diesel Mechanic Cost: Call-Out Fees Explained (2026)

Mobile diesel mechanics charge a flat call-out fee plus hourly labor and sometimes mileage. Here's what that breaks down to in 2026, what changes the price, and how to avoid getting overcharged on a roadside repair.

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Cost Guides
7 min read

DPF Cleaning vs Replacement: Which One Actually Costs Less?

DPF cleaning costs a fraction of replacement, but it only works on a filter that isn't physically damaged. This guide breaks down real 2026 pricing, when cleaning fails, and how to avoid paying for a new filter you didn't need.

Diesel and gas pickup trucks parked side by side illustrating diesel vs gas truck cost of ownership
Cost Guides
7 min read

Diesel vs Gas Truck Cost of Ownership: The Real 2026 Numbers

Diesel trucks cost more upfront and need pricier repairs, but they often win on resale value, towing durability, and fuel economy under load. This guide breaks down purchase price, fuel, maintenance, DEF, and resale so you can run the real numbers before you buy.

Fuel pump display showing diesel price per gallon at a truck stop station
Cost Guides
6 min read

Why Is Diesel So Expensive? The Real Reasons Explained (2026)

Diesel usually costs more than gas because of tighter refining rules, higher federal and state taxes, stronger global demand, and seasonal blending costs. This guide breaks down the price per gallon, compares it to gasoline, and shows where owner-operators can actually save money.

Mechanic checking glow plug wiring on a diesel engine during a cold weather no-start diagnosis
Diagnostics & Repair
8 min read

Diesel Won't Start in Cold Weather? Troubleshooting Guide

A diesel that won't start in cold weather usually points to gelled fuel, a weak battery, or a glow plug system that hasn't warmed the cylinders enough. This guide walks through each cause step by step, what a shop checks first, and realistic repair costs for 2026.

Diesel mechanic reading SPN fmi codes on a handheld scan tool in a truck engine bay
Diagnostics & Repair
7 min read

Reading Diesel Fault Codes: SPN and FMI Explained

SPN and FMI codes are the language your diesel's computer uses to report problems. This guide breaks down what each number means, how to read a code off your scan tool, and what to do next — before you pay a shop to tell you.

Diesel mechanic reading scan tool codes to diagnose diesel limp mode in a truck engine bay
Diagnostics & Repair
8 min read

Diesel Limp Mode and Engine Derate: Causes and Fixes

Diesel limp mode cuts power to protect your engine from bigger damage. Learn what triggers a derate, how to read the warning lights, and which fixes you can try before booking a shop diagnosis.

Close-up of a diesel turbocharger housing showing what a turbo looks like mounted on the exhaust manifold
Diagnostics & Repair
7 min read

What Does a Turbo Look Like? A Visual ID Guide

A diesel turbo looks like a snail-shaped metal housing bolted to the exhaust manifold, with a round compressor wheel on one end and a ribbed turbine housing on the other. This guide shows you how to spot one, tell it apart from other engine parts, and catch early signs of failure.