Chevy Tahoe - Dexcool

The intake manifold gasket failed after only 72,421 miles on a 1999 Chevrolet Tahoe. Mechanics attribute the failure to Dex-cool in the cooling system even though the system was back-flushed and coolant was replaced every two years. I was advised that this is "a common problem" with GMC vehicles and that I can expect additional failures of the cooling system in a relatively short time due to Dex-cool.
The internet indicates that premature intake manifold failure in GM products with Dex-cool is common and that there may also be an engineering problem with differential heating between the gasket and the manifold that aggrevates the leak and allows the Dex-cool to enter the engine.

Repairs cost $511 and I was without a vehicle for two days.

I have a 1999 Chevy Tahoe that was experiencing overheating and gauge fluctuatons. First call from the dealer states they needed to change the thermostat, flush the radiator and everything would be fine; second call they tell me the intake was leaking coolant into the engine, third call they tell me all the hoses were very volatile and needed to be replaced, grand total $1,293.00.

Before I brought the truck in, it ran perfect other than the overheating. The day I picked the picked the vehicle up it ran worse than when I brought it in. That was May 2003, here it is August 15, 2003 and what is my truck doing, out of Dexcool coolant and overheating again!

I purchased a 1998 Tahoe from Classic Chevrolet in February of 2002. The Tahoe had 45,000 miles on it when purchased. I purchased an extended 2-year, 20,000 mile warranty on the vehicle. At 67,000 miles, the truck overheated on the way to work. I took it to a Goodyear repair shop and they replaced the water pump for $500, flushed the system and pressure tested it for leaks. At 74,000 miles, a few months after the water pump, I now have to replace the intake gasket.
Apparently, GM uses dexcool (the orange coolant) and it corrodes plastic and aluminum when there is low coolant in the vehicle. I did some research and apparently this is a highly typical and common problem, with one symptom being the heater not blowing hot air, which happened 2 weeks after I purchased the car, while it was under warranty. Of course, the warranty did not cover A/C or heater problems, so I suffered through this, not knowing it probably was the intake gasket going out the whole time. I would guess they were aware of the problem when I purchased the truck.
Since then, the wheel coverings rattle on all four tires, interior parts fall off like they were stuck on with scotch tape, the battery was replaced a week after I purchased the vehicle, and the starter has also been replaced.

I have missed more work than I care to mention. I have spent $1,700 on total repairs, including $1,150 just on the cooling system problems. The intake gasket is a $14.99 part and they charge $650 to replace it, knowing that it is a design defect.