bout Fuel Injectors And Periodic Cleaning

Cleaning fuel injectors is a service frequently recommended by dealers and repair shops, but unless there are noticeable signs of clogged injectors (such as a rough idle, stalling, poor acceleration or high emissions levels) it might not be necessary. One tipoff is that fuel injector cleaning is not typically listed on automakers’ routine maintenance schedules.

Many shops promote a quick/easy injector service that runs a cleaning solution through the injectors while they’re still mounted in the engine. A more thorough (and expensive) process for severely clogged injectors requires removing the injectors and cleaning them on a machine designed for that purpose.

Fuel injectors clog when deposits build up over time and thousands of miles; when that happens, they don’t deliver the fine mist of gas that provides maximum performance and efficiency. If that happens, you’ll notice a loss of engine performance or lower fuel economy.

The type of gasoline you use also can be a factor. All gasoline is required to contain detergents that prevent carbon deposits, varnish and other gunk from forming in the fuel system, but not all brands use the same amount. Lower-priced brands often use only the minimum, but the so-called Top Tier brands use more detergents, and some vehicle manufacturers recommend them because of that.

Detergents have been required by the EPA since 1995 because many vehicle owners complained of clogged injectors and fuel-system deposits. Not only has gasoline gotten better since then, but so have the injectors, so problems aren’t as widespread as they used to be.

However, gasoline direct injection, a more sophisticated injection system that operates under higher pressure, is becoming commonplace in engines, and some GDI systems have proved to be more prone to clogging than regular fuel injection.

That’s why some manufacturers, such as Hyundai and Kia, among others, recommend adding a fuel system cleaner to your gas tank periodically if you’re not using Top Tier gas on a regular basis.

Many other gasoline additives that are supposed to clean fuel system parts are also available over the counter, and they may help keep things clean enough so that fuel injector cleaning isn’t necessary. The additional detergents found in Top Tier gas should do the same thing, which might be all your fuel system needs.

Change Oil Every 3,000 Miles

No, you don’t, according to every auto manufacturer we’ve talked to. The main advocates of the 3,000-mile oil change schedule are those who would profit by it: repair facilities, quick-lube chains and service departments at some new-car dealers.

Years ago it was a good idea to change the oil and filter frequently, but because of advances in engine materials and tighter tolerances, as well as the oil that goes into engines, most manufacturers recommend intervals of 7,500 miles or more.

Ford, Volkswagen and Porsche, for example, recommend oil changes every 10,000 miles. So does Toyota on several engines, including the Prius’ 1.8-liter four-cylinder and the Camry’s 2.5-liter four-cylinder. BMW says owners can go up to 15,000 miles between oil changes (with synthetic oil).

The intervals vary by manufacturer and engines, so consult your owner’s manual or maintenance schedule to see how often to change the oil in your vehicle and what type of oil to use. You may be surprised. We were surprised to learn that the Camry’s 2.5-liter engine requires 0W20 synthetic oil, for instance.

Manufacturers suggest you change oil more often for “severe” driving conditions, such as frequent trailer towing, extensive stop-go driving or idling in traffic, driving in extreme heat or cold, or frequent short-distance driving in which the engine doesn’t reach full operating temperature.

Some car companies, Ford and General Motors among them, equip most vehicles with oil life monitors that tell you when it’s time to change the oil based on vehicle speed, engine temperature, climate conditions, number of cold starts and other factors. They can all cite examples from owners who say the oil-life monitors indicated they could go even longer than the recommended change intervals.

If you’re nervous about going 10,000 miles or more between oil changes, then do it every six months, when you probably should also have your tires rotated (also explained in your owner’s manual). GM says to change your oil at least once a year even if the service indicator warning light doesn’t come on. With longer recommended intervals between oil changes, it’s more important to check the oil level at least once a month to make sure you have enough.

But to change oil every 3,000 miles is probably wasting money. Environmentalists say it also adds to the glut of used oil that must be recycled or disposed, and the state of California is trying to discourage the practice.

If the guy at the quick-lube shop says he’s only trying to help you when he recommends frequent oil changes, consider this: It is not in the interest of an auto manufacturer for you to suffer premature engine failure caused by worn-out oil. If that happens, they might have to pay for repairs under warranty and probably will lose you as a customer. Yet, they’re the ones advising you to follow longer oil-change intervals.