UPDATE 1-Navistar loss narrows as warranty costs fall, truck sales rise

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June 5 (Reuters) - Truck and engine maker Navistar International Corp reported a smaller quarterly loss as warranty expenses fell and truck sales improved.

The company's warranty expenses had been rising because its redesigned engines failed to get regulatory approval in 2012.

The engine was based on a technology to limit emissions of nitrogen oxide without using additive urea.

Navistar has developed a new engine based on the selective catalytic reduction (SCR) emissions technology, which is more fuel efficient.

The company said its warranty expenses fell 13 percent in the second quarter ended April 30 due to the introduction of the new SCR engines and lower warranty costs on older engines.

Net loss attributable to Navistar narrowed to $297 million, or $3.65 per share, from $374 million, or $4.65 per share, a year earlier.

Revenue rose 9 percent to $2.75 billion.

Analysts on average had expected revenue of $2.72 billion, according to Thomson Reuters I/B/E/S.

Navistar's shares closed at $35.45 on the New York Stock Exchange on Wednesday.

The stock had fallen about 7 percent this year to Wednesday's close, compared with a 9 percent rise in the Dow Jones U.S. Commercial Vehicles & Trucks index.

(Reporting by Abinaya Vijayaraghavan in Bangalore; Editing by Kirti Pandey)