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.

Nearly all new diesel engines come equipped with a turbo-charger. The turbo-charger is a lot like 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. But because the turbo-charger is so powerful, great care must be taken to make sure the air entering the turbo-charger is clean and clear of debris. If a small piece of debris were to enter the turbo as it was spinning at max speed, it's possible that one or more compressor blades would shatter (ruining the turbo). Therefore, it's incredibly important that the air filter on your diesel is clean and properly installed. Most manufacturers equip their vehicles with electronic sensors that will tell you to check or replace your air filter, but you can manually check the air-filter using the restriction gauge. The restriction gauge, found on near the filter, will tell you if your air filter has become too clogged to protect your turbo-charger. If the gauge indicates your filter is too clogged, you should replace it immediately. Unlike a gasoline engine, failure to change your diesel's air filter will lead to thousands of dollars in engine damage relatively quickly -- even in just a few hundred miles. In fact, it's a good idea to keep a spare air filter on hand at all times.

Even without the turbo-charger, diesel engines have lots of maintenance items that are especially important. Fuel filters are extremely important for proper performance because diesel fuel, unlike gasoline, contains a relatively large amount of impurities. For example, the typical gasoline fuel filter might only need replacement once every 30,000 miles. Yet many manufacturers suggest diesel fuel filters be replaced in as little as 10k miles (depending upon driving conditions). Make sure to check your owner's manual to find out what your manufacturer suggests. Also, use the same service station every time you refuel if possible. If you're favorite service station has bad fuel, you'll find out relatively quickly and you can save yourself money by finding a new fuel source.

In addition to containing a relatively large amount of impurities, diesel fuel also contains water. Even though small amounts of water will not hurt your diesel engine, most modern diesels are equipped with water separators. Depending upon your manufacturer, you may need to manually purge the water from your diesel's fuel system as often as once a month. Check your owner's manual for instructions. If you don't purge the water from your diesel's fuel system, you may experience poor performance and fuel economy. Many service facilities will perform this task for you at little or no charge.

Colloquially, diesels are sometimes called "oil burners". That's because diesels, unlike gasoline engines, typically burn some of the engine's lubricating oil during normal use. Obviously, if your engine is burning oil on a regular basis it's extremely important to check the oil level between oil changes. When checking the oil, make sure the engine has cooled for at least 30 minutes and that the vehicle is level -- that way, you know all the oil has had time to drain out of the top of the engine. Once you've pulled the dipstick, your owner's manual will explain when you should add oil based on the dipstick reading. Remember - if you don't check the engine's oil levels between changes, you could permanently damage your motor.

Diesel engines are especially sensitive to cold temperatures. Diesel fuel, for instance, may start to "gel" (turn from a liquid to a semi-solid) at temperatures below zero. At temperatures below freezing, diesel engines often start harshly and warm-up slowly. At very low temps (below -10 F) normal diesel engine oil will not protect the engine from friction. For all these reasons, it's important to remember to use your diesel's block heater if outside temps ever dip below zero. In fact, if you can afford the electricity, I suggest you plug-in your block heater any time the outside temperature dips below freezing. This will protect your engine, keep your fuel warm, make for quick and easy start-ups, and help your engine warm-up quickly. To locate your block heater plug-in, check your owners manual. Typically, they are wire-tied to a harness behind the bumper.

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.

To summarize, it's very important that new or first-time diesel owners review their engine manual. In addition to normal vehicle maintenance, diesel owners should keep a close eye on their air filter restriction gauge, change the fuel filter often, always check engine oil between oil changes, purge water from the fuel system as required, and remember to plug-in the block heater any time outside temperatures drop below zero degrees Fahrenheit. When you do all these extra tasks, your diesel engine will reward you with 200,000+ miles of good service.