I just acquired a low mile 2004 ZR2 and of course me being me it was broken and I had to tow it home.

I knew it had a overheat issue that wound up being bad intake gaskets that was compounded by a bad thermostat and fan clutch. The whole coolant system was jammed up with all kinds of junk but after 7 flushs I'm starting to see some lite at the end of the tunnel. The amount of chocolate colored water and radiator rocks is slowing down. I'm contemplating adding some form of filter to the heater core inlet line to catch some of the junk. But, that will be a project for another weekend.

Once I get done with the flushing and it's time to put some coolant and distilled water in the rad, I'll have make the decision on which coolant to use. I think the current Dexcool is safe to use but the green stuff has always been good.

 

I ditched the Dex and went to green when I replaced my radiator a little while back. Lots of others have done the same. I've had nothing but issues with Dexcool on any GM older than about 10 years old...

 

I only have one other GM with DeX . It's a 2005 Saturn Relay or as like to call it the Love Machine. It's got DeX and it hasn't caused any problems yet but with going through this ordeal makes me me want to atleast give it a flush and add some fresh.

 

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