To dex-cool or not to dex-cool...

It's time for me to flush the coolant. I am wondering what to put in. Dex-cool again? Prestone Extended Life? Ol' greeny? Strawberry Quik? I have noticed a bit of brownish sludge on the walls of my coolant overflow reservior, which makes me hesitate putting dex-cool in again. I am leaning towards Prestone EL, since I heard it is like dex-cool but isn't dex-cool. Any suggestions?

If you choose to use anything other than Dex-Cool I suggest that you do a very very good job of flushing out the system with water first.

other extended life coolants are good and dont have that mud that happins when dexcool is used.the prestone in the silver jug says that it is completely compatable with dexcool. i dont reccomend green stuff unless you put lots of warning lables under the hood telling tecnicans that it has been completely changed out and not to add pink stuff in error [dont mix pink and green, they contaminate each other]

Here is my two cents. Do not use anything else but Dex-cool in a vehicle that has it in it. If GM put it in from the factory, thats the best thing for that engine/radiator. Manufactures spend a lot of time and money fine tuning motors to run on specific parts/fluids. Now, I'm not saying to go to a GM dealer and by GM Dexcool coolant. As long as you buy a Coolant approved by GM that is Dexcool. I personally used Prestone when I changed mine last time.

Like I said, just my 2 cents. It just makes since to me.

I heard on another forum that distilled water should be mixed in when replacing the coolant.Anyone else hear of this?

There is a (possibly true) rumor that the sludge is caused by some reaction between the Dex-cool and the salts and stuff in tap water. Yes, I would strongly recommend using distilled water wherever water is needed (radiator and esp. the battery).