MPG maintenance, stay on top of these five maintenance tasks

By Paul Abelson, senior technical consultant

Maintenance of your truck and trailer is more than just an exercise in prevention. Sure, a consistent maintenance schedule will reduce the likelihood of unexpected downtime from a breakdown. But, a good maintenance schedule keeps money in your pocket in a different way too – improved fuel economy.

Maintaining your truck may not result in huge fuel cost savings like aerodynamics or changing driving habits can, but taken all together, a well maintained truck can save up to a half-mile a gallon in typical on-highway long haul use.

Everyone knows fuel prices will not continue at these low levels. Think how much that could mean in fuel savings if and when the cost of fuel inches back up.

Here are the Top 5 maintenance areas that will save you the most on fuel consumption.

#1. Wheels and tires

Tires flex. If they didn’t, we’d have awfully bumpy rides. But tires are designed to flex within limits. Not enough flex and the suspension and all that rides on it gets hit with hammer blows. Too much flexing and the tires get destroyed.

Maintaining proper air pressure in tires prevents this unwanted flexing. The air in the tire supports the truck. The tire structure just keeps air in and assures the tread stays in place for traction. When a tire flexes too much, it has the kind of heat build-up that leads to a catastrophic tire failure. Maintain tire pressure and you’ll save 2 percent or more by eliminating that excessive flexing.

But there’s more to taking care of your tires than just keeping them inflated properly. Have you ever seen a trailer bounce down the road, especially when empty? That may be due to tar strips or possibly out-of-balance tires.

When the heavy spot on the tire flexes back after contact with the ground, there’s a force that wants to pull the tire off the ground. That bouncing spends energy that comes from your fuel tank.

There are many products that automatically balance tires, all reasonably inexpensive. Savings may only be 1 percent or less, but because the devices are so inexpensive, return on investment is great.

#2. Alignment

Picture the energy (that’s your fuel) you’ll consume trying to drag your truck sideways instead of rolling straight down the road. That’s what happens when your tires are out of alignment. It may be drug 40 feet or as much as 400 feet to the side for every mile you travel.

Assuming only 200 feet per mile, that’s almost 4 percent sideways travel, or 19 sideways miles after 500 miles of driving. That takes a great deal of energy – energy that comes directly out of your fuel tank. Keeping wheels properly aligned can save up to 3 percent, depending on the amount of misalignment, by eliminating sideways movement.

#3. Lubrication

Preventive maintenance intervals are usually based on oil drain. Oil should be changed regularly, but not because oil stops lubricating. Rather, it’s because the additives deplete and oil loses properties that protect the engine.

Among them is dispersancy, oil’s ability to keep soot, metal shavings and other contaminants suspended throughout the oil. As the oil carries more contaminants, it becomes thicker. That alters its viscosity. The oil thickens and more energy (again we’re talking fuel here) must be consumed pumping the oil throughout the engine and filters. Viscosity’s importance in improving fuel economy is why the latest engines are using 10W-30 or thinner oils instead of the old standby,


The same is true of transmissions and drive axle lubricants. SAE J1321-type and coast-down tests have demonstrated that synthetic oils, especially with lower viscosities, can cut fuel consumption by 1 percent or more. Anything that reduces friction saves energy, and that translates to improved fuel economy.

#4. Underhood adjustments

Drive belts are a common source of energy loss, wasting fuel unnecessarily. They use friction to transfer mechanical force to drive accessories mounted away from the crankshaft. These include air conditioner compressors, alternators, power steering pumps, external water pumps and more.

Today, many are mounted to the engine block. They use automatic belt tensioners to maintain proper drive friction on the belt. When belts are changed, inspect the tensioners, too. They weaken over time.

#5. Cleanliness

It makes sense to keep your truck clean, if only for personal reasons. Accumulated dirt in your cab can get into heat and air outlets and restrict flow. That forces heaters and air conditioners to run longer, often at higher loads. Again, the source for the extra energy is your fuel. Reduce the load and increase fuel economy.

Depending on truck condition, proper maintenance can reduce fuel use as much as 5 percent in total, perhaps more.