Owners and lessees of Kia Sorento sport-utility vehicles are suing the company over an alleged design defect that causes sudden engine failure.

The putative class action, filed Jan. 3 in federal court in Newark, alleges Kia has failed to repair the defect under warranty in 2002-09 Sorentos with the 3.5-liter, 24-valve DOHC V6 engine made by Hyundai.

According to the complaint, in Robinson v. Kia Motors America, 13-cv-00006, the engine crankshaft sprocket balancer sticks out too far and weighs too much, causing the spring guide pin and front pulley bolt to break.

This allegedly sets off a chain reaction that shreds the power steering, battery charging and cooling system belts, causing heat buildup, and loss of steering control and power.

Each of the three class representatives “literally muscled the car to the side of the road,” says class counsel Shmuel Klein, a solo in Mahwah.

The problem typically manifests itself soon after the five-year, 100,000-mile warranty is up, the suit claims.

The suit charges the problem could have been remedied as a preventive measure by Kia dealerships, but the company instead continued to make vehicles with the defect.

Kia allegedly has “done no more than temporarily repair” the defect when reported within the warranty period and has refused to provide repairs outside of it.

According to the complaint, the engine failed on a 2005 Kia Sorento owned by class representative Rose Ciros of Sewell in May 2010. She claimed her car was still under warranty but, when she took it to Turnersville Kia, she was told it needed a new engine that would not be covered by the warranty.

She allegedly rejected the dealer’s $3,800 proposal and had the car fixed by an independent repair shop for $1,457.

The suit says any applicable statutes of limitations have been tolled by Kia’s knowing and active concealment of the alleged defects.

Klein says Kia has known about the defect for years. He cites 64 complaints by owners on www.pissedconsumer.com and another 20 on www.my3cents.com.

The suit includes a count for violation of the New Jersey Consumer Fraud Act on behalf of a subclass of New Jersey Kia owners, and breach of express warranty and breach of implied warranty of merchantability on behalf of subclasses from each of the states.

The suit also claims violations of the Magnuson-Moss Warranty Act and statutory and common law, and seeks an order requiring Kia to recall, repair and/or replace the vehicles.

The suit seeks certification of a nationwide class of tens of thousands of current and former owners and lessees.

Scott McKee, director of public relations for Kia Motors America, declines comment.