WASHINGTON -- U.S. auto safety officials upgraded a probe into Ford Windstar minivans following a raft of new complaints about corrosion in the vehicles.
The National Highway Traffic Safety Administration, in a posting on its Web site Wednesday, said it has launched an engineering analysis -- an advanced stage of its ongoing investigation -- that covers about 550,000 Windstar minivans from the 1999-2003 model years.
Ford has recalled more than 600,000 of the minivans in the United States and Canada because rear axles can corrode and break. In the United States, the recall began in August and is limited to 22 northern states where salt is used to treat roads during the winter.
NHTSA said its latest investigation is focusing on new corrosion complaints in the front of the vehicles.
The safety agency, according to the posting on its website, has received 346 complaints of corrosion and broken front subframes on the Windstar.
The subframe supports the minivan's engine, transmission, steering rack and front suspension. If cracked or excessively corroded, steering control on the minivan can be impeded.
Three crashes and one injury have been reported to the agency.
NHTSA said most of the latest complaints have been filed by motorists in cold weather states. Some Windstar owners have also cited problems on the right side of the vehicle with the routing of air-conditioning lines, the agency said.
Ford spokesman Wes Sherwood told The Associated Press the automaker was "fully cooperating with the government on the investigation."
Under the recall launched in August, replacement rear axles won't be available until the beginning of 2011, Ford says. The company said it is working with parts makers to speed up axle supplies. In the meantime, Windstars have begun piling up on some dealership lots, waiting for parts and service.
Ford has said owners who have vehicles with cracked axles will be offered a repair or alternative transportation until parts become available. In some cases, the automaker is providing rental vehicles and repurchasing some Windstars.
In November, NHTSA issued a consumer advisory urging owners to have the minivan inspected immediately by dealers. At the time, the agency said that only about 75,000 vehicles had been brought to dealers for inspection.