7 Things That Every New Diesel Owner Should Know

If you're new to diesel engines, there are quite a few things that may come as a surprise to you. First of all, diesel engines generate tremendous amounts of torque. This allows them to tow or haul thousands of pounds of materials or equipment, and they can often accelerate very quickly even when loaded down. Yet despite their incredible power, they are surprisingly fuel efficient. These qualities of efficiency and power may someday make diesel engines more common than gasoline engines, but for now it's important for any new diesel owner to know that diesel engines require more maintenance than gas engines. In fact, failure to perform these essential maintenance tasks could result in your diesel suffering major engine damage.

Most likely, your diesel came equipped with a turbo-charger. The turbo-charger is similar to a jet engine - there are compressor blades inside the turbocharger that can spin at 20k or 30k rpm. As these blades spin, they force clean outside air into the engine, increasing engine efficiency and performance. Because the turbo-charger is so powerful, great care must be taken to make sure the air entering the turbo is clean and clear of debris. If, for instance, a small particle or piece of debris were to enter the turbo as it was spinning at max speed, it's possible this particle could cause one or more compressor blades to shatter. Therefore, it's incredibly important that the air filter on your diesel is clean and properly installed. Most manufacturers have equipped their vehicles with sensors that will tell you to check your air filter, and nearly all diesels have air-filter restriction gauges. The restriction gauge will tell you if your air filter has become too clogged to protect your turbo-charger, and you should immediately replace the air filter if the restriction gauge indicates to do so. Unlike a gasoline engine, failure to change your diesel's air filter will lead to thousands of dollars in engine damage relatively quickly. For this reason I suggest you keep a spare filter in your vehicle just in case.

Even if you don't have a turbo, there are lots of other maintenance items that are especially important on diesel engines. Fuel filters are critical to proper diesel performance because diesel fuel, unlike gasoline, contains quite a few impurities. While a gasoline engine fuel filter might require replacement once every 30k miles (mostly as a precaution), diesel fuel filters can become clogged in as little as 10k miles. Make sure to check your owner's manual to find out what your manufacturer suggests. If at all possible, use the same service station every time you refuel. That way your chances of buying a bad tank of diesel are reduced.

Diesel fuel, in addition to having a lot of impurities, also contains water! Even though small amounts of water will not hurt your diesel engine, water does reduce economy and performance. Therefore, most modern diesels are equipped with fuel-water separators. Depending upon your vehicle manufacturer, you may need to manually purge the water from your diesel's fuel system as often as once a month. Make sure to check your owner's manual for instructions. In some cases, if you don't purge the water from your diesel's fuel system you will experience poor performance and fuel economy. Luckily, many service facilities will perform this task for you at little or no charge. They'll also dispose of the contaminated fuel/water mixture.

A lot of old-timers call Diesel engines "oil burners" because, unlike gas engines, diesels burn some of the engine's lubricating oil during normal operation. In fact, diesel engines under heavy use can burn two or three quarts of oil between changes. That's why it's especially important to check your diesel's oil level regularly. When you check the oil make sure the engine has cooled for at least 30 mins and that your vehicle is on level surface. The owner's manual will explain when you should add oil based on the oil dipstick reading. Remember to do this often -- if the oil level falls too low you will suffer engine damage.

Another diesel engine quirk is that they are especially sensitive to cold temperatures. Untreated diesel fuel can "gel" (turn from a liquid to a semi-solid) at temperatures below zero. At temperatures below freezing, diesel engines usually start harshly and warm-up slowly. At extremely low temps (below -10 F) most diesel engine oil will not protect the engine from friction because it will be too viscous. For all these reasons, it's important to use your diesel's block heater anytime outside temperatures dip below zero (F). If you can afford the electricity, my recommendation is to plug-in your block heater any time the outside temperature dips below freezing (32 F). This will protect your engine by keeping your fuel and oil warm, make for quick and easy start-ups by pre-heating your glow plugs, and help your engine warm-up quickly by pre-warming the engine coolant. To locate your block heater's plug-in, check your owners manual. Usually they're wire-tied to a harness behind the bumper. If you engine doesn't have a block heater, one can be installed for a small charge.

While all new engines have a short break-in period, new diesel engines usually have a break-in period that lasts 500 or 1000 miles (check your manual to find out). Usually, the manufacturer recommends that you avoid driving at sustained speeds (i.e. long trips on the highway) during this period. Additionally, most manufacturers suggest you not tow or haul anything during this period as well. Once the initial break-in is over, it's not uncommon for your diesel to continue to improve in power and efficiency for the first 20k or 30k miles. Unlike gas motors, which often stop improving in power and efficiency after 3k to 5k miles, diesels need lots of time and use to reach their peak efficiency and performance. In fact, most long-time diesel owners will tell you that their engine didn't really start to truly perform until a year or two after they bought it.

In summary, any new or first-time diesel owner should read their diesel's engine manual. They should also make sure to keep a close eye on the air filter restriction gauge, change the fuel filter often, always check engine oil between services, purge water from the diesel fuel system, and use the block heater anytime outside temperatures drop below zero degrees Fahrenheit. By taking the time and effort to do these extra tasks, your diesel engine should reward you with 200,000+ miles of service.