As long as it's dex-cool aproved your good to go!

 

The key to the five year life of dex-cool is not to get any air in the cooling system. I use ph test strips to check my a/f twice a year. I get five years plus on all my rigs, and with six of them it adds up.

 

thanks for all of the advice...hope this helped others too

my coolant reservoir was very low, hadn't checked it in a while. I filled it back but now I'm worried about air in the system. I will flush it.

 

The dealers and customers hate dex-cool, BUT it is better stuff than the green Prestone. It is normal for it to get clumpy, and normal for it to look rust colored. The solid stuff goes away when it goes through your warmed engine block, so it is not causing any problems to your engine, even if it looks like sludge when you open the cold radiator cap. Customers don't like this stuff because it just doesn't look right. If you have a pre-2000 car, you may have slightly different dex-cool in your car, they have changed it a little to keep it looking more like red cool aid than rusty mud. Flushing every once in a while is good. 150,000 mile coolant is like 100,000 mile spark plugs and 7k oil changes. Fine, if you don't enjoy the performance of your vehicle.
If you do flush yourself (the dealer has a better set-up and charges about $45) make sure you remove the topmost coolant lines - going to the throttle body. Refill with red stuff only, until the red stuff is coming out of the upper TB coolant lines. Run the car for 20 seconds, then remove the upper TB lines again and fill until red KoolAid comes out.