Oil changes might not be needed so often

DETROIT -- Most major automakers agree: The adage that you should change your car's oil every 3,000 miles is outdated, and even 5,000 miles may be too often.

Ford Motor Co. became the latest manufacturer to extend its oil life guidelines, making public that it is raising the recommended oil change interval from 5,000 miles to 7,500 on its newly redesigned 2007 models and all subsequent redesigned or new models.

The company, like many other manufacturers, said higher oil quality standards and new engine designs were responsible for the change, which affects vehicles driven under normal conditions.

"The oils have advanced a lot since the days when 3,000 miles were the typical oil drains," said Dennis Bachelder, senior engineer for the American Petroleum Institute, an industry organization that sets quality standards. "They're certainly more robust than the oils of 10, 15 years ago."

These days, motor oils start with a higher-quality base oil than in the past, and they have more antioxidants that make lubricating properties last longer and other additives that keep deposits from forming on engines, Mr. Bachelder said.

Pete Misangyi, Ford's supervisor of fuel lubricants, said the company conducted numerous fleet and laboratory tests with newer oils before it raised the interval.

Some manufacturers, such as Honda Motor Co. and General Motors Corp., have stopped making recommendations on all or most of their models, instead relying on sensors that measure oil temperature extremes and engine revolutions over time to calculate oil life and tell drivers when to get the lubricant changed. Oil can lose its lubricating properties if it runs at too low or too high of a temperature.

Peter Lord, executive director of GM's service operations, said oil can last 12,000 miles or even more for many drivers who don't run their vehicles in extreme heat or cold or tow heavy loads. "It really does depend on the individual customer and how they've used the vehicle," he said.

When to change oil is not without controversy, though.

Toyota Motor Corp. reduced its change interval from 7,500 miles to 5,000 in 2004 in part because it found that more drivers ran their vehicles under severe stop-and-start and short-trip conditions that cause oil to deteriorate more quickly, said company spokesman Bill Kwong.