Consumer complaints about DexCool in GM Engines

Consumer complaints about DexCool in GM Engines: "Andras of Chula Vista CA (11/28/01):
We purchased a 1998 Chevrolet Blazer from Bob Baker Chevrolet in El Cajon, California, in early 2000. The vehicle had 40,000 miles on it, was in good shape, and according to the dealer, had just had a complete service. At about 70,000 miles, the car started to shift hard between first and second after it had been driven for a while. When it cooled down (that's subjective - the temperature gauge never moved) the problem went away. I checked the fluid levels - all were good - then opened the radiator. I was suprised to discover that the radiator was filled with brown sludge, especially as the car used Dexcool - a 100,000 mile/no service needed coolant."