2004 Cadillac Cts Starting Problem
 

Hi,
This is my first post so bear with me. I have a 2004 Cadilac CTS 3.6l engine. My problem occurs only once or twice every ten start-ups. It sounds like a grinding noise when I crank the engine. The engine struggles to start, sometimes it starts, sometimes it doesn't. When it doesn't I wait about 5 seconds and turn key and it fires right up. No engine codes. Slight coolant leak from mid engine. I add about 1/2 quart of dexcool every 3 days. I have included a video on YouTube of the problem. Any help would be appreciated. Thanks.