Hi, In the manual it says to use dex-cool fluid.

Is this really necessary, or can another 50/50 be used to top up the fluid in the expansion bottle.

 

I personally would spend a few bucks for the DEX-COOL 50/50. Not sure when the last time your coolant was changed. For your 06 with DEX-COOL you should be flushing and changing your coolant in 2011 anyway. 5 years or 150,000 mi.

If you do want to change over to standard glycol based anti-freeze then your entire system should be flushed twice and then filled with the glycol based anti-freeze. Change glycol based every 3 years or 40,000 miles. See you are not saving anything by changing to glycol based anti-freeze. Add up the flushes, and shorter intervals of change and you are actually spending more $.

Directly from DEX-COOL:

CONTAMINATION:
Mixing conventional green coolant with DEX-COOLŽ will degrade the service interval from
5yrs./150,000 miles to 2yrs./30,000 miles (50,000 km) if left in the contaminated condition. If contamination occurs, the cooling system must be flushed twice immediately and re-filled with a 50/50 mixture of DEX-COOLŽ and clean water in order to preserve the enhanced properties and extended service interval of DEX-COOLŽ.

 

Thanks fot the info. Where do you get Dex-cool stuff.

 

Pretty much any auto parts store shoudl have it!

 

Personally, I am not a big fan of the Dex-Cool. I just never really liked it. When i bought my hummer, I had to get the radiator replaced due to the common leaking problem the 06 had, so I had the shop flush my system and switch me to anit-freeze. It seems that she runs a few degrees cooler with the "green stuff". But I am sure the Dex-Cool stuff works just fine, it does last longer, and GM wouldnt have used it if it didnt work. Just my $.02