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First of all, I am embarrassed to say that I didn't know there were two different types of radiator coolant. (Seriously, that's like not knowing that there two different types of engine oil. :rolleyes:) Anyway, the engine apparently had Dexcool in it when the top radiator hose blew off while stopped at a red light in downtown Detroit on our way to a Detroit Lions game. We got it pulled over fairly quickly and shut it down. No permanent damage done fortunately. We got the hose reattached and, after the game, stopped at a gas station between the stadium and car and bought some green coolant (two gallons) and put it in just to get the car home, which we did. Fast forward: the car has a new radiator and has had several gallons more of green coolant added to it, to the point where it's pretty much made a complete changeover from Dexcool to green. The overflow tank was also drained. (I still have to flush/burp the heater core.) Here's my question: first of all, I know that you cannot mix the two. I also know that Dexcool has had problems when air gets into the system. I would like to just stay with the green. Is this going to cause problems in the long run, especially given that the engine previously had Dexcool in it? (FWIW, the engine was rebuilt about 45K ago and has a stage 1C cam.) I'm hearing that the silicates in the green don't play nicely with the aluminum components, and it has me worried.
 

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If it was my car I would get rid of the green fluid completely with a proper flush & put back the dexcool. If this was not completely flushed out properly you are going to have both fluids in there which is no good.
 

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It's more than fine. I've been running green for probably 7 years and 100k now. Just don't mix the two... fully flush and replace with the proper mixture of either one. Also, for what it's worth, apparently the Dexcool issues of old are no more.
 

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The Dexcool issue was actually not the Dexcool but an intake manifold gasket problem. In short, the gaskets were the wrong material, and when they finally deteriorated the results were predictable. Since Dex isn't Glycol based material compatibility was obviously overlooked in the early years of Dex-Cool. Tsk Tsk

Here is the problem with using Green in an aluminum motor.

I don't know a ton about Dex-Cool chemical wise, but Green is Glycol based and over time as the inhibitors break down it is supposed to change color to indicate corrosion. In an aluminum motor it does not change color.

Should the EG 50/50 become corrosive for any reason, it will go unnoticed and you would start seeing leaks. Glycols have a habit of breaking down into their base acids over time. That's part of the inhibitors job to prevent that from happening, but eventually that runs out.

There was another thread in here suggesting 100% PG coolant, but I also consider that a bad idea. I compared it to EG based, though.... not DexCool.
 
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