Car care that's necessary, unneeded — or even harmful

Q: I just saw an exposé on a quick-lube place trying to sell engine flushing and fuel-injector cleaning. It was startling to see this person's engine destroyed because of the engine flush. What is your take? Are these ever a good idea? How can I know what my car really needs?

A: This topic will surely stir some discussion, prompting me to clean out my inbox.

It is common for some shops to sell services that differ from or exceed manufacturer recommendations. A good place to begin: Dig out the maintenance schedule from your glove box and see what is truly recommended. Newer vehicles typically have extended service intervals for oil changes, filter replacement and other common services, and likely don't mention a recommendation for renewing coolant hoses and brake fluid — among other jobs many in the repair business believe are important.

I'm opposed to pressurized engine flushing for several reasons. It's not required or recommended by any vehicle manufacturer I'm aware of — in fact, some specifically recommend against it. Also, I'm not convinced it's actually effective, as much of an engine's sludge is in the upper end and not effectively rinsed by a flush.

There is also considerable debate about sludge chunks being broken loose and blocking the oil-pump pickup screen, impeding engine lubrication.

A more gentle and generally accepted approach: Add a half-quart of automatic transmission fluid (an excellent solvent), run the engine at idle for a half-hour, then change the oil.

Maintaining a clean engine is important, especially when certain engines have sludge buildup issues (some Audi, Chrysler, Lexus/Toyota and VW models). If your driving consists mainly of short trips, high temperature operation, or you tow a trailer, it's important to change your oil frequently with an oil meeting the American Petroleum Institute's SM rating, which is currently the best. Insist on it. If your drive cycle includes a half-hour or more of freeway driving each day at moderate load and temperature, sludge problems are much less likely.

My recommendations on additional maintenance services:

Fuel injector/intake tract cleaning: Only if performance issues warrant it.

Power steering system flush: A waste of money.

Cooling system flush: Drain, refill with new coolant every four years, renew hoses, skip the flush.

Brake fluid renewal: Good idea. Do this every four years.

Transmission flush: Skip this, but install a drain plug on the oil pan next time it's removed. Renew fluid (only half will come out) every 24,000 miles. Renew the filter — if applicable — every other time.

Fuel filter: Every 50,000 miles.

Oil change: If over 5,000 miles or six months, change oil at "30 percent oil life remaining" (if your car has an Oil Life System readout).

Send questions to under-the-hood@juno.com.