Water Outlet Tube

Last year at this time, I was driving along in the heat of the summer and all of a sudden my temperature gauge shot up to HOT. I immediately pulled over and saw the coolant leaking from near the water pump. It turned out to be a water outlet tube failure. The tube is a smaill plastic elbow that enters the engine block. It was a $15 part but about $ 150 more in labor. This year, almost exactly 1 year to the day, the same thing occurred. It was the second time in 2 years I had to repair the water outlet tube. Is this a known vulnerable part of the cooling system that causes many failures? Any ideas on how I can prevent these sudden, heat-related breakdowns? The car is a well-maintained 1998 Lumina LTZ 3.8L with 108,000 miles on it. No amount of preventive maintenance has helped me prevent the recurrence of this problem...

check the condition of your belt tensioner. As the spring ages, it loses tension, and can cause the tensioner to start to jump. The vibration this causes will crack the plastic elbows that go between the block and the tensioner bracket.