Many automobile owners are spending more than they need on motor oil, believing that it should be changed every 3,000 miles even though almost no manufacturer requires such an aggressive oil-change schedule.
The long-held notion that the oil should be changed every 3,000 miles is so prevalent that California officials have launched a campaign to stop drivers from wasting millions of gallons of oil annually because they have their vehicles serviced too often.
"Our survey data found that nearly half of California drivers are still changing their oil at 3,000 miles or even sooner," said Mark Oldfield, a spokesman for the California Department of Resources, Recycling and Recovery, which has launched the Check Your Number campaign to encourage drivers to go with the manufacturer's recommendations.
Improvement in oils, friction proofing and car engines have lengthened the oil-change interval, typically 7,500 miles to 10,000 miles for most vehicles.
Changing motor oil according to manufacturer specifications would reduce motor-oil demand in California by about 10 million gallons a year, the agency said. The state has created a website, checkyournumber.org, where drivers can look up the suggested motor-oil change interval number for their vehicles.