Higher maintenance costs at its aluminum wheel manufacturing sites contributed to Superior Industries International Inc. posting lower net income in the third quarter compared to a year ago.

The Van Nuys-based company reported net income of $4.2 million, or $0.16 per diluted share, on revenues of $207.1 million for the quarter ending Sept. 30. For the same period in 2010, the company had net income of $10.4 million, or $0.39 per diluted share, on revenues of $183.7 million.

During the quarter, Superior shutdown two of its manufacturing plants for one week for maintenance, which affected financial performance, the company said, adding there were labor expenses and wheel development activities that had increased since a year ago.

“We are fully committed to take necessary actions that we believe will enable us to achieve greater productivity, efficiency and reliability in our factories and meet customer demand,” Superior Chairman, CEO and President Steven Borick said in a prepared statement.