GM launched the Cadillac XTS in China at a lavish event in February, part of GM's effort to build its luxury brand with Chinese customers. Cadillac sales were up big in August. Photo credit: GM

China has been a big bright spot for General Motors (GM -0.04%) in recent years. GM is the market-share leader in China, which has become the world's largest auto market, and its Buick and Chevrolet brands are well-known and popular with Chinese car shoppers.

August was another solid month for GM in China, with sales up a little over 11%. But there were some interesting trends behind the numbers, as both Buick and Cadillac posted outsized sales gains. In this video, Fool contributor John Rosevear digs into the latest results from GM's China effort -- and looks at what's working, and what isn't, for GM right now in this huge market.