Green stuff to Dexcool == Grey Goo

When I bought my Jeep it had the green stuff and a slight cooling system rust problem.

About three months ago I flushed my cooling system using some prestone super flush stuff. I hooked it up to the hose and let it run for about an hour, then used compressed air to blow out as much of the water as possible. Of course I did it with the jeep facing uphill, possibly my big mistake. I refilled with Prestone DexCool and Prestone anti-corrosion additive.

Now I get home from sea and I pop my radiator cap and there's a huge booger of the dreaded grey-goo. And lots of tiny bits of goo floating around in my antifreeze. So yay lucky me I get to flush it again just what I love doing flushing cooling systems. At least it's hot outside so I won't mind getting wet.

On the plus side the rust problem DOES seem to have gone away, either that or I just can't see it now because dexcool is orange (way to go, GM).

My question is what happened? I thought dexcool and the green stuff were supposed to be compatible. Even if they aren't, I flushed like crazy. Perhaps the anti-corrosion additive had something to do with it...

The other question, stick with dexcool or go back to green stuff? Can I even find green stuff that isn't really just green dexcool?

I'm guessing the additive and the Jeep pointing up hill are the culprits-- nose down, heat on (to empty the heater core) and flush again. I have used both the ethelene glycol (green stuff) and the Dex Cool with little or no noticeable difference, but I now use the Prestone AF due to availability. The only negative breports I've heard about the Dex Cool came from Ford when they were testing their version of it in some of their aluminum head/iron block engines-- but that shouldn't concern those of us with iron/iron engines.:repair:

--Shorty

P.S. my Navy base is bigger than yours!

Uh-oh!! Sounds like you have a classic case of Dexcool mixing.....That was one of the big problems with the orange coolant. When mixed with the older style, it would congeal like yours has.

As to what you do now.....I would flush the system extremely well, with the chemical flush additives. Then I would re-fill the entire system with water, and run that for a day or so......drain and flush again. This should allow you to completely refill with fresh coolant. Prestone AF (should be green) is at most parts stores, and claims to be 100% compatible with all other types of AF.

Personally?? I avoid the orange Dexcool like the plague....or a pre-96 minivan

I never heard of anyone switching to dex-cool, when i was driving a chevy everyone was switching from dex-cool to the green stuff

I'll look around for Prestone AF. I'm familiar with grey goo issues from my VW days, when they switched from the blue stuff to the red stuff (aka liquid gold, $50 a liter or something).

I read in a thread somewhere that most of the new "green" coolants have the same ingrediants as DexCool and you have to hunt around to find the old style green stuff. I seem to recall cofirming this by carefully reading labels, although they don't list ALL their ingrediants so it's hard to say for sure.

How come you switched in the first place?

Dexcool is nasty stuff. Erodes pretty much everything.

I switched to try and resolve the aforementioned rust issue. My impression from researching the forums is that only the factory GM dexcool is really horrible and the 3rd party dexcool is not corrosive and doesn't form orange crystals all over your water pump and tstat. Anyway I found a couple gallons of old skewl super-hi-tox green stuff so I'll put that in.

When I drained I didn't really see any more grey goo so I guess it was mostly just one big booger in the filler neck.

Forgot to mention I also put water wetter in it.

I was told by a mechanic that if you are going to switch either way you had to be sure to get ALL of the old stuff out or it could cause corrosion problems. However, a person I know switced their blazer from red to green and I haven't seen a problem yet. Knowing the mechanic that did it, I doubt it was flushed very well either. Personally, I wouldn't switch.