Does the mercedes ml350 have a timing belt or chain?

The 2015 Mercedes-Benz ML350 uses a timing chain rather than a timing belt. The timing chain usually doesn't need to be replaced unlike the belt which has to be replaced every so often. The reason why the chain doesn't need to be replaced is because it is on the inside of the engine and gets help from engine oil whereas the belt is on the outside of the engine and is exposed. If it used a timing belt it would need to be replaced every 60,000 to 100,000 miles or so but since it uses the chain You only need to inspect it every 150,000 miles or so. To inspect it You just take off the valve cover and look at the tension and the sprockets.