DexCool

I just bought a 97 Sierra. I see it uses DexCool which
I am not familiar with. I opened the radiator cap and
was suprised to see oily coolant. It looks more like
salad dressing. Is it supposed to look like that even
if it is crapped out? It is sort of clear with brownish
(I'm colorblind) swirles. I am going to have it flushed
and refilled with DexCool. It also smells rusty. Any
comments would be appreciated. It runs at a steady
middle of the temp guage which, without looking, I think
is 210. Thanks

Check the reservoir too. The Dex-Cool is orange, if it looks brown or oily, it's possible someone poured regular green coolant in. The only way to rid this is to flush the cooling system. Make sure Dex-Cool is used when replacing the old (contaminated) coolant.