I've flushed my system once each year. 1st time to change a thermostat gasket. 2nd time to do the thermostat gasket again because it leaked. (use RTV thermostat seal with the gasket, that solves that problem). 3nd time to change the water pump. 4th time to replace a cracked head. I'm just waiting for the 5th thing to go wrong.
Seriously, though, this coolant should be fine for several years at least. If you really want to know, get a test strip and check the pH of the coolant. Coolant becomes acidic over time. As long as it's basic (pH>7 or 8), it's probably fine.
The real issues with Dexcool were in vehicles that had coolant flowing through nylon intake manifold gaskets such as in the 3.8L motors. Switching to an aluminum framed gasket solved that problem, although in my Buicks I flushed the system out and switched to G-05. However, because there is no coolant flowing through the intake manifold gasket of the 5.3, this is not an issue so the Dexcool can stay.
Seriously, though, this coolant should be fine for several years at least. If you really want to know, get a test strip and check the pH of the coolant. Coolant becomes acidic over time. As long as it's basic (pH>7 or 8), it's probably fine.
The real issues with Dexcool were in vehicles that had coolant flowing through nylon intake manifold gaskets such as in the 3.8L motors. Switching to an aluminum framed gasket solved that problem, although in my Buicks I flushed the system out and switched to G-05. However, because there is no coolant flowing through the intake manifold gasket of the 5.3, this is not an issue so the Dexcool can stay.
