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

Detailed view of a diesel car badge with blurred background, captured in Prague.
Maintenance
8 min read

What Is Diesel? A Plain-English Guide to Diesel Fuel

Diesel is a petroleum-based fuel burned by compression instead of a spark. This guide covers how diesel differs from gasoline, cetane rating, fuel types, storage rules, and how to keep your fuel system healthy.

A striking green semi-truck parked outdoors with a dramatic cloudy sky backdrop.
Maintenance
6 min read

Oil Change on a Diesel Engine: Types, Intervals and Why It Matters

A diesel oil change isn't just gas-engine maintenance with a bigger filter. Diesel oil fights soot, acid and heat that gasoline oil never sees. Here's the right oil type, interval and cost for your engine — plus what happens if you skip it.

Close-up of a person refueling a car with a gas nozzle at a station.
Maintenance
7 min read

What Happens If You Put Diesel in a Gas Car? (And What to Do Now)

Put diesel in a gas car by mistake? Here's what actually happens to the engine, the warning signs to watch for, and the right steps to take before you turn the key.

A bright red and yellow MINOL tanker truck with labeled compartments parked outdoors under a cloudy sky.
Maintenance
7 min read

Is Diesel Flammable? What Every Diesel Owner Should Know

Diesel doesn't ignite like gasoline, but it's not harmless. Learn why diesel is classified as combustible, not flammable, what flash point and autoignition temperature actually mean, and how to handle and store diesel fuel safely around your truck, RV, or equipment.

A rural gas station showing diesel price, featuring trucks and American flag.
Maintenance
7 min read

6.7 Powerstroke Fuel Filter Service Guide: Intervals & Costs

Learn the OEM fuel filter interval for the 6.7 Powerstroke, how the water separator protects your CP4 pump, and step-by-step service tips. Includes 2026 pricing and a DIY-vs-shop checklist.

Detailed view of engine parts showcasing camshaft and cylinder head mechanics.
Maintenance
8 min read

Does a Diesel Engine Have a Spark Plug? (No — Here's What It Uses Instead)

Diesel engines don't use spark plugs — they rely on compression ignition. Learn how diesels actually start fuel burning, what glow plugs really do, and when to replace them.

Diesel fuel sign on metal pipes against a dark black background at night.
Maintenance
7 min read

Diesel Fuel Explained: Cetane, Gelling and Storage Life

Diesel fuel isn't one simple liquid — cetane rating, temperature, and age all change how it burns and how long it lasts. Learn what cetane number really measures, why diesel gels in cold weather, how to prevent it, and how long you can safely store fuel before it breaks down.

A vibrant orange Freightliner truck drives on a highway through a dry, scenic landscape in El Salvador.
Maintenance
7 min read

Diesel Engine Families Explained: Power Stroke, Cummins & 3.0 Duramax

Ford Power Stroke, Ram Cummins, and GM Duramax — including the light-duty 3.0 Duramax — each follow different service intervals and wear patterns. Here's what sets them apart and how to keep each one running right.

A diesel pickup truck on an open interstate highway
State Regulations
7 min read

Diesel Emissions Rules by State: What Pickup, RV and Fleet Owners Need to Know

Which diesel emissions rules are federal, which states test, and how to keep a Power Stroke, Cummins or Duramax legal without losing reliability.