How Proper Vehicle Maintenance Improves Fuel Efficiency

Fuel costs are a major cost of doing business when operating a fleet of any size. Purchasing new vehicles can significantly reduce fuel cost, but can be prohibitive as a capital investment. Most fleet managers are unable to replace their entire fleet and may continue to operate older vehicles for some time. This means that proper maintenance to improve and maintain fuel efficiency is an important, and cost-effective, way of reducing overall costs.

Here are a few things you can do to maintain fuel efficiency in cars and trucks:

1. Use higher quality engine oil. Look for oil that is specifically marked Energy Conserving – these oils contain additives that reduce friction and thus improve efficiency (and can also extend the life of the engine). Always use the grade of engine oil recommended by the manufacturer and change the oil as often as needed.

2. Keep tires at the correct pressure. Under-inflated tires increase road friction and thus reduce fuel efficiency by as much as 3%, as well as reducing safety. Tires should be checked at least once a month, more often in heavy use vehicles. When you replace the tires, get low rolling resistance tires (these reduce drag). Also keep tire alignment correct.

3. Make sure all vehicles are tuned up regularly – at least once a year or more often for high-mileage vehicles. This is particularly important if you are still running older vehicles without ECUs or with less well-designed ones.

4. If you are still running vehicles that have carburetors, changing the air filter when you change the oil can increase efficiency by as much as 14%. New vehicles do not benefit as much (although changing the air filter can still help protect the engine).

5. Check engine air intakes. Your engine needs to breathe – any restrictions on the air intake or exhaust decreases power output and thus wastes fuel. Check for leaks regularly.

6. Check and maintain air conditioning units, especially in hot climates. Air conditioning can be essential for comfort (and even safety in some environments), but running the air conditioning requires fuel. Keep the condenser and evaporator coils clean and free from obstructions and make sure the refrigerant level is neither too low nor too high.

7. Clean diesel particulate filters regularly. This is usually about every 200,000 miles, but check recommendations from the engine manufacturer. Cleaning DPFs helps protect truck engines from damage as well as improving efficiency.

8. Check the engine cooling fan. The fan clutch can get stuck in the “on” position, causing the cooling fan to run constantly and wasting fuel. If the fan is not cutting in at all, this can cause engine damage.

9. Be sure to check aero devices on large trucks. If they are not working, they are not doing their job and reducing drag. (And, of course, if they require driver input, make sure your drivers are using them). Broken aero devices should be repaired or replaced as quickly as possible. With automatic devices (ones which operate without driver intervention), make sure that their operation is checked regularly, and bear in mind that this requires observing the vehicle at speed – most devices activate at 40 mph.

10. Check your gas cap. A broken or cracked gas cap, or one which is not seated properly, can result in gas or diesel evaporating. While this might seem like it would be a tiny amount, it can add up.

Overall, fuel efficiency is improved by keeping up with vehicle maintenance, especially of tires, engine oil, and climate control systems. Keeping everything properly maintained will also extend the lives of engines, improve safety, and reduce cost.