If you're new to owning a diesel, there are a lot of maintenance items you should be aware of. Diesel engines, while extremely powerful, are also somewhat fragile if not maintained properly. In fact, failing to complete any one of these basic maintenance tasks could result in your diesel breaking down. But if you properly care for your diesel, you'll have an engine that generates tons of torque, accelerates any big load, and offers you the kind of fuel efficiency that you would expect from a much smaller motor. Diesel's many benefits even have some people predicting that one day in the future all people will own diesel engine vehicles instead of gasoline -- so these maintenance tips might be very important to you down the road. In all likelihood your diesel has a turbo-charger. The turbo-charger, much like a jet engine, has compressor blades inside it that spin at 20k or 30k rpm. These blades force clean outside air into the engine, thereby increasing engine efficiency and performance. However, because the turbo-charger is like a jet engine, great care must be taken to make sure the air entering the turbo is clean and clear of debris. For instance, if a small piece of debris were to enter the turbo as it was spinning at max speed it's possible one of the compressor blades would shatter as it struck the debris. These shattered pieces would then strike other blades, shattering them, until the time when the entire turbo has been destroyed. That's why it's incredibly important that the air filter on your diesel engine is clean and properly installed. To help you, most vehicle manufacturers equip their vehicles with an electronic sensor that will tell you when to check your air filter. Additionally, nearly all turbo-diesels have air-filter restriction gauges. This restriction gauge will tell you if your air filter has become too clogged to protect your turbo. If the gauge indicates a new filter is needed, you should replace it immediately. For all these reasons, 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.
Unlike most modern gasoline engines, new diesel engines often have a manufacturer specified break-in period. During this period (usually the first 500 or 1000 miles) your owner's manual will tell you to avoid driving at sustained speeds and to refrain from towing or hauling. In other words, it's best to avoid any long highway trips or any heavy use for the first few days or weeks. Once this initial break-in period is over, it's not uncommon for your diesel to continue to break-in for the first 20,000 or 30,000 miles. Unlike gasoline engines, which are truly broken-in after 3k to 5k miles, diesels need lots of time and use to reach their peak efficiency and performance. Most long-time diesel owners will tell you that their diesel didn't really start to perform until the engine had a year or two of use.
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.
