Auto Repair For Dummies, 2nd Edition
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Regular maintenance is absolutely imperative if you want a diesel engine to last, and every diesel owner will probably encounter some pitfalls and problems.

Although diesel engines require no ignition tune-ups and tend to last longer without major repairs than gasoline engines, they do require regular low-cost maintenance, mostly in the form of frequent oil and filter changes. The urea injection systems that reduce nitrogen oxide emissions also need refilling, which is usually done as part of regularly scheduled maintenance.

If you own a conventional gas-powered vehicle and you get sloppy about maintenance and don’t change the oil often enough, you’ll probably end up with an engine that has aged prematurely. If you own a diesel and do the same thing, you may end up with an engine that’s prematurely dead. The same goes for changing filters: A dirty fuel filter can impair a conventional vehicle’s performance, but dirty fuel can clog a diesel’s fuel injection system, and you may need expensive professional help to get back on the road again.

As a rule, you shouldn’t try to clean or adjust a diesel’s fuel injectors yourself, but if you maintain your vehicle according to the directions in the owner’s manual, they can last 100,000 miles or more. After all, truckers have always preferred diesels because they find them to be tough, reliable, and cheap to run and maintain.

Most diesels are designed so that the owner can perform regular maintenance chores without an undue investment of time and money.

If your owner’s manual doesn’t advise you on a specific maintenance task, or if you have no manual, amble on over to your dealership’s parts department and ask to see a copy of the service manual for your vehicle (some book stores and public libraries may also have them). A quick look at the proper sections should tell you whether you can do the job yourself. If you’re not sure, ask one of the service advisors at your dealership to show you where the oil, air, and fuel filters are located and what’s involved in changing or servicing them. Most service facilities are pretty nice about that kind of thing.

Typical maintenance tasks include:

  • Changing the lubricating oil

  • Changing the air filter

  • Changing the fuel filter

  • Bleeding the fuel system

  • Draining the water separators (see below)

Draining a Diesel Engine's Water Separators

Diesel fuel can easily become contaminated by water because diesel fuel absorbs water more than gasoline does. For this reason, many diesel vehicles feature a gadget called a water separator that collects water from the fuel. It’s usually located on or near the fuel filter. If your vehicle doesn’t have one, you can have one installed. The part shouldn’t be terribly expensive, and it can save you a bunch of money on repairs.

Although a few water separators are self-cleaning, most need to be manually drained: You just turn a little drain valve called a petcock and empty the water from the collection chamber of the separator.

It’s a good idea to check the water separator weekly at first to see how fast it fills up under normal conditions when you’re driving on fuel from your usual source. If the fuel contains a lot of water, you may want to consider buying fuel elsewhere.

About This Article

This article is from the book:

About the book author:

Deanna Sclar is an acclaimed auto repair expert. She has appeared on hundreds of radio and TV shows, including NBC's Today show and the NBCNightly News. Sclar lectures internationally on the ecological impact of vehicles and is active in promoting residential solar energy programs. Sclar is also the author of Buying a Car For Dummies.

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