BEIJING (Reuters) - U.S. automaker General Motors Co GM.N said on Wednesday its second-quarter sales in China increased 0.7 percent to 858,344 vehicles compared with the same period a year ago.

FILE PHOTO: A Cadillac Escalade SUV by General Motors Co of the U.S. is displayed during a media preview of the Auto China 2018 motor show in Beijing, China April 25, 2018. REUTERS/Joe White/File Photo

However, the second-quarter growth rate of vehicle sales in China eased compared with the January-March quarter, which saw an increase of 8 percent. The slowdown was mainly due to lean sales of Buick brand vehicles in the April-June period.

Buick sales dived 16 percent to 230,454 vehicles in the second quarter compared with a year-ago period. Sales of Cadillac, Chevrolet and other brands climbed in the second quarter from a year ago.

Buick sales declined due to a technology shift by the brand to offer a number of models with smaller-displacement, turbo-charged engines, said a Shanghai-based spokeswoman for General Motors.

“Buick is leading the industry in the deployment of the cutting-edge small displacement engines, but it takes time for sales to pick up after technology changeovers,” the spokeswoman said.

While the 1-litre and 1.3-litre turbo-charged engines match or exceed the performances of non-turbo 4-cylinder engines that were replaced, the new engines also offer greater fuel efficiencies.

“We believe the adoption of these engines will be commonplace in China in the years ahead,” she added.

In the first-half of 2018, GM and its local Chinese joint venture partners posted record sales, selling 1.84 million vehicles, up 4.4 percent from the first half a year ago.

The previous first-half record was during the January-June period of 2016 when GM sold 1.81 million vehicles.

The Detroit automaker has stopped reporting monthly China vehicle sales, saying the monthly snapshot does not accurately reflect the market. The company now issues sales reports only on a quarterly basis.