I have never suspected dex cool to cause a leaking problem. I just always put that towards wear and tear. But if you do have that rust colored sludge I sugest repair the leak, flush and use a different coolant. I think it is Havoline that makes an orange coolant that is good. But the green is good as well.

 

i agree i would not think that dex-cool would make it leak... but the WHOLE cooling system was replaced a little over a year ago.. I don't think I should have rust & silicon flowing thru the system THIS soon..

 

That does seem odd. Maybe it was not flushed proper and there was contaminents in the system. As you can read in a link in one of the posts that dex does not play well with them.
Good luck on fixing it

 

I have a 97 Blazer with all the same problems. The rusty sludge, intake gasket, heater core, thermastat and so on. I fixed it all with flushing out the dex-cool and torqueing the intake bolts, along with some aluma seal and some jb weld. This fix was only gona be a 2 week deal till I bought a new ride. That was 30,000 miles ago. Not bad for a $20 fix. At 147,000 miles who can say its the dex-cool, I think it's more of a time issue. Also this is an aluminum block/heads motor, so is the rusty color rust or just the dex-cool? If it was rust the block would be long gone by now.

 

http://www.freep.com/apps/pbcs.dll/a.../1014/BUSINESS

 

lol.. my car had that when I bought it, didnt know it when I first got it though. I'm pretty sure its all out now though since I flushed the radiator.. maybe not though. Anyway, I would like to think that GM wouldnt develop something thats going to harm the engine, especially since its been on the market this long. Maybe Dex cool is the culprit, but I would like somethin to back that up. thanks for the new though, I won't shoot the messenger or anything, just don't want to believe it..

 

after thinking about that for a minute, im regretting the fact that my dad refilled it with dex-cool again.. I'll have to get some of that orange Havoline madmike was talking about..

 

Another issue with dex. I was running Valvoline synthetic in my wife's Montana V6. When the intake gasket started to leak the anti-freeze went to the crankcase. The resulting mixture turned to jelly, after taking off the filter nothing would run out when turned upside down. It took four engine flushes just to get oil to flow to the rockers after that.