SACRAMENTO, Calif. — For decades, automotive repair has been seen as a grease-stained poor relation of the dollar-laden sales segment in the auto industry.

Not now.

As new-car sales have plunged along with consumer confidence, more people are spending to keep their current cars running. Auto service and repair arguably have become the lifeblood of the industry.

Dealership service/repair operations, independent auto shops and businesses that cater to do-it-yourself mechanics all are doing well. At most dealerships, service/repair operations are now the primary money-makers.

"Our service and parts departments are among the most important, consistently profitable departments," said Rick Niello, president of Sacramento-based Niello Co., which operates 13 mostly high-end foreign-make auto dealerships in Northern California. "I would say service and parts probably account for 75 percent of our profitability. ... In past years, it was less than 50 percent."

Niello said the company's dealerships serviced about 100,000 cars in each of the past two years, five times what they were doing in 2001.

The Niello Collision Center is a 4,500-square-foot operation that works on cars of all brands. Niello said the small center does about $400,000 a month in body work. When the economy improves, he wants to open a 40,000-square-foot facility nearby.

Mel Rapton Honda, which just completed its move into a new 77,000-square-foot, $14 million dealership, also leans heavily on service.

The department has 54 state-of-the-art bays in a cavernous building. Katina Rapton, president and general manager, said service covers more than 85 percent of the dealership's expenses.

"The industry average is less than 50 percent, so that shows you how important it has become," she said.

Independent auto service shops also are reporting a steady stream of customers.

Richard Hale, owner of Walt's Auto Service in Citrus Heights, Calif., said "we're staying steady. I just ran the numbers, and we're almost exactly where we were in January and February of last year.

"If you can keep your business at 2007 and 2008 numbers in this economy, you're doing pretty well."

Hale said current customers are more willing to opt for comparatively expensive service, like an engine overhaul or replacement, "instead of going out and buying a new car. They just don't want to go out and spend $30,000 or $40,000 right now for a new car."

Even though customers are looking to extend the life of their cars, some also are gambling that nothing goes wrong. Hale and other local independent shop operators said some customers are putting off scheduled maintenance, to stretch their dollars.

Another trend: More customers are paying in cash.

"Customers used to just throw it on their credit cards, but we're not seeing as much of that now," Hale said. "Putting it on the credit card is not the answer now."

For some, doing the work themselves is the best way to save money.

"An oil change might cost only $20 or $30 with some of the specials they have going now, but why spend that when you can change your own oil?" said Gregory Smart, a Sacramento construction worker who has two pickup trucks.

"What I save on an oil change will buy my family groceries for almost a week. The other work I do myself will save me even more than that."

Walt King, a retiree in Carmichael, Calif., is another dedicated do-it-yourselfer.

"I'm trying to hang on to my two cars as long as they keep running, and both have more than 100,000 miles (on them)," King said. "I'm saving money by buying the parts and doing the work myself."

The do-it-yourself approach of Smart and King is reflected in the performance of Memphis-based AutoZone Inc.

While U.S. automakers have been rolling up massive losses and fighting to survive, AutoZone last week far exceeded Wall Street's expectations by reporting earnings of $115.9 million for its quarter that ended Feb. 14, up 9 percent from the comparable period last year.

Alldata LLC, the Elk Grove-based AutoZone subsidiary, provides automakers' service and repair information, shop-management software and other services to the professional auto-service industry. It also provides manufacturers' information for most motor vehicles sold in the United States from 1982 to 2008 — a service that do-it-yourselfers can sign up for, starting at $26.95 a year.

Alldata said both its commercial and private subscriber lists have seen consistent growth for the past year.

Bill Rhodes, AutoZone's chairman, president and chief executive, said the company is "benefiting from the general slowdown in the economy. We think a greater number of people may be focusing on maintaining their vehicles given today's economy."