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Mechanics Corner: Diesel vs. gas in RTVs: What’s the difference and what’s best for you?

Eric Goins Published on 12 November 2015

Just as no two farms or ranches are alike, the same can be said for rough terrain vehicles (RTV) and utility terrain vehicles (UTV). Capabilities can vary greatly depending on the manufacturer and engine type and, because of this, it’s critical to do your homework before purchasing a new vehicle.

An important consideration to keep in mind is whether diesel or gas works best for your operation, depending on the intended use of the vehicle, and ultimately how your decision affects future engine maintenance. To determine whether diesel or gas is the right fit for your individual needs, we first need to break down the differences between the engines.

Unlike gas engines, diesel engines rely on compression rather than a spark to ignite the air-fuel mixture. And because it’s carbureted, there are no spark plugs and no spark plug wires on a diesel engine, which is why gas engines with those components are typically easier to start.

Diesel fuel also has a higher flash point to ignite vapor and, in general, gas will ignite more readily than diesel. Diesel engines are liquid-cooled, and gas engines rely on air-cooling.

And, while diesel fuel costs more than gasoline, a diesel engine makes more efficient use of its thicker, higher-energy fuel so that it packs a bigger punch per unit than gasoline.

Now that we understand the technical differences between the two options, the next step is to determine how the vehicle will be used because you must match the utility vehicle to its intended application. There are a number of UTVs that are specifically targeted for recreational purposes but are then limited in their utility capabilities.

We’ve heard many times of buyers who purchased a recreational-type utility vehicle with a simple, clutch-less belt-drive transmission only to find out after several months of slow, light load usage that these simple transmissions are ironically the most susceptible to belt wear under those work conditions.

By buying the right utility vehicle from the start, one that is matched for your workload needs and offers the capacity, passenger capability and implements required, you can get significantly more use out of your investment.

Taking a deeper dive into usage, if transportation and light-duty work applications are the order of the day, then gas-powered UTVs are the way to go. A great perk of gas-powered models is that electronic fuel injection is becoming a must-have standard feature.

The benefits of electronic fuel injection can be easily remembered by the three E’s of efficiency, emission capabilities and easy-starting versus a carbureted model. Today there are many gas-powered models on the market that offer this feature plus a comfortable ride with convenient hauling capabilities.

For work that requires extra power, a UTV with a diesel engine can really maximize the potential for performance, longevity and fuel availability. It’s these features that are causing diesel use to increase in many markets. With more torque and better fuel economy, diesel engines can outlive their gas counterparts while maintaining their long-lasting performance.

Some manufacturers specialize in diesel and hydraulics, which power the dump-beds and the power steering functionality for increased ease of use. For even more power where you need it, diesel engines with hydrostatic transmissions can be a great choice because they’re essentially tractor-type transmissions rather than belt-drive or mechanical transmissions.

If you’re working specifically with commercial applications that can run the gamut of uses, then you’ll need a versatile workhorse that gets the job done efficiently in all weather conditions. For this reason, it’s important to buy a powerful UTV that delivers dependable performance as well as all-day comfort.

And again, when considering whether to buy gas-power versus diesel, how and where the UTV will be used should again be an important consideration. Liquid-cooled diesel engines perform better in hot, dusty operating conditions and are a great choice if heavier-duty work is performed most days.

However, if the job site requires mostly light-duty work and personnel transportation, then gas may be your best bet.

Finally, whether you choose a gas- or diesel-powered utility vehicle, performing daily maintenance checks and interval service will save excessive downtime and costly repairs in the future. Here are some maintenance tips to get you started:

Diesel engines

  • Because diesel engines rely on compression rather than a spark to ignite an air-fuel mixture, the first maintenance lesson for diesel owners is to throw away their spark plug wrenches. On diesel engines, there are no spark plugs, no spark plug wires and no bothersome maintenance on an ignition system.

  • Diesel fuel has a higher flash point to ignite vapor. In general, gas will ignite more readily than diesel, but caution should be used with either fuel type.

  • Keep diesel and gas containers well marked and separated. Gasoline will damage a diesel engine.

  • Liquid-cooled diesel engines perform better in hot, dusty operating conditions than their air-cooled counterparts. Maintenance requirements include a routine check of the coolant level, mixture and hoses.

Gas engines

  • Most importantly, drain the fuels from the carburetor and lines.

  • It is very important to keep the gasoline in your tank fresh. Ethanol aging in your fuel turns to varnish and gums up jets and other internal parts of the carburetor, requiring expensive cleaning to assure proper operation again.

  • For gas engines, it is important to clean around the engine. And, similar to diesel engines, it is easier to clean before storing versus after. Remove debris after the machine sits for long periods of time.  FG

Eric Goins is the RTV product manager for Kubota.