Diesel vs Gas Truck Maintenance: What Costs More and Why

One of the most common questions we hear from truck owners at Murphy's Autocare is some version of: "How much more does it cost to maintain a diesel?" It's a fair question, especially if you're shopping for a new truck and weighing the diesel option against the gas V8.

The short answer: diesel maintenance costs more per service visit, but the math gets more nuanced when you look at the full picture. Here's an honest breakdown based on what we actually see at our Beavercreek and Centerville shops.

Oil Changes: Diesel Costs More

This is the most obvious difference, and it's unavoidable.

Gas truck oil change: A typical gas V8 (like the 5.3L or 6.2L GM, or the 5.0L Ford) holds 6-8 quarts of oil and uses a conventional or synthetic blend that costs $8-12 per quart.

Diesel truck oil change: A 6.7L Powerstroke holds about 13 quarts. A 6.7L Cummins holds about 12 quarts. Diesel oil costs $12-18 per quart for a CK-4 rated product. The filter is larger and more expensive too.

Rough comparison:

A diesel oil change typically runs 1.5 to 2 times the cost of a gas engine oil change. That's a real difference — but it's not the 3x or 4x that some people expect.

Fuel Filters: Diesel Has an Extra Service Item

Gas trucks have a fuel filter, but it's usually a lifetime component inside the fuel tank. You never service it. Diesel trucks have one or two serviceable fuel filters that need replacement every 15,000-20,000 miles.

This is an additional maintenance cost that gas trucks simply don't have. Budget $100-200 for each replacement depending on the engine. Over the life of the truck, fuel filter replacements add up to roughly $500-1,000 per 100,000 miles.

DEF Fluid: A Small Ongoing Cost

Modern diesel trucks use DEF (Diesel Exhaust Fluid) for emissions compliance. The truck has a DEF tank that needs periodic refilling.

Cost: DEF costs about $3-5 per gallon, and most trucks consume 2-3 gallons per 1,000 miles. That's roughly $6-15 per 1,000 miles — a small but real ongoing cost. You can buy DEF at most gas stations and auto parts stores, or have us top it off during service.

Gas trucks don't have this cost at all.

Coolant System: Similar, But Diesel Is More Critical

Both gas and diesel trucks need cooling system maintenance — coolant flushes every 100,000 miles or 5 years. The cost is similar for both.

The difference is consequences. A cooling system failure on a gas truck is inconvenient and can cause engine damage. A cooling system failure on a diesel truck under heavy load (towing on I-75 in July) can be catastrophic — head gasket failure on a diesel is a significantly more expensive repair than on a gas engine.

Brakes: Diesel Often Wins

Here's where diesel starts to catch up. Diesel engines produce strong engine braking (especially with an exhaust brake), which reduces wear on the mechanical braking system. Diesel truck owners who tow frequently often find their brake pads last 20-30% longer than the same pads on a gas truck towing similar loads.

This isn't a huge savings per service, but over the life of the truck it offsets some of the higher oil change costs.

Transmission: Depends on Use

Both gas and diesel trucks need transmission service — fluid changes every 60,000-100,000 miles depending on use. The cost is comparable.

However, gas trucks towing near their maximum capacity tend to run the transmission harder than a diesel doing the same work. The diesel produces more torque at lower RPM, which puts less thermal stress on the transmission. If you tow regularly, the diesel's transmission may need less frequent service.

The Big Picture: What Does It Actually Cost?

Let's compare total scheduled maintenance over 100,000 miles for a typical ¾-ton truck:

Diesel scheduled maintenance costs roughly twice as much as gas over 100,000 miles. That works out to about $20-40 more per month.

Where Diesel Makes Up Ground

The maintenance cost difference is real, but it doesn't tell the whole story:

Fuel economy. Diesel trucks typically get 20-30% better fuel economy than their gas counterparts. For a truck averaging 15,000 miles per year, that's $1,000-2,000 in fuel savings annually at current diesel prices. Over 100,000 miles, fuel savings can more than offset the higher maintenance costs.

Longevity. Diesel engines are built to withstand higher compression and thermal loads. They routinely run 250,000-400,000 miles with proper maintenance. Gas V8 truck engines are durable too, but diesel engines generally have a longer service life before major internal work is needed.

Resale value. Diesel trucks hold their value significantly better than gas trucks in the used market. A well-maintained diesel truck with 100,000 miles commands a substantial premium over the same truck with a gas engine.

Towing capability. If you tow regularly, the diesel's torque advantage means it works less hard doing the same job. This translates to less overall wear on the drivetrain and a more comfortable towing experience.

When Gas Makes More Sense

Diesel isn't always the right choice. If you rarely tow, drive mostly short trips, or put fewer than 10,000 miles per year on your truck, the higher purchase price and higher maintenance cost of a diesel may never pay back. A gas V8 is simpler, cheaper to maintain, and perfectly capable for light-duty use.

The Bottom Line

Diesel maintenance costs more — roughly double over the life of the truck. But if you tow regularly, drive significant miles, or plan to keep the truck long-term, the fuel savings, durability, and resale value typically offset the maintenance premium. It's not a clear win for either side — it depends on how you use the truck.

Whatever you drive, Murphy's Autocare services both gas and diesel trucks at our Beavercreek and Centerville locations. We'll help you stay on the right maintenance schedule for your engine, your driving conditions, and your budget.

• Beavercreek: 937-426-2886
• Centerville: 937-433-0140

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