So recently my blazer started to overheat a little. I figured I was just low on antifreeze, and I was. But when I went to check the antifreeze level in the radiator there was a little this brown chunky substance around the rim of the cap. For the time being I disregarded it but when I went to check the radiator antifreeze level this morning that brown chunky stuff was a lot more prominent and I had to clear it out. Should I be worried about this????

 

Has anyone put any Radiator stop leak into the cooling system, that you're aware of? These products can form sludge around the radiator fill neck "under the cap". I'd try flushing the system, and refilling it with fresh water and antifreeze. While flushing, remember to turn on the heater, so the heater core will be flushed as well.

 

Sounds like somebody mixed some "green" anti-freeze with the "orange" (DexCool) anti-freeze. You can google it, but I think that's a no-no. You should probably have it flushed before you plug something up.

 

And be sure to replace the radiator cap with a new one.

 

there is a service bulletin for this. Mine was as you described years ago, it was a 3 hour process to clean out the cooling system. mine had only ever had the orange in it at the time and it turned into a rusty soup

 

GM Service Informatio - Dexcool System FLush

 

That's what I've got going on right now, too. Ugly brown crappy looking coolant. Mine is pretty diluted, though, due to a radiator leak. Every time it's low, I just add water. I'll be getting a new radiator after the holidays, so I'm planning to flush all that crappy orange crap out and go back with regular ol' green at the same time.

I think the Dex Cool is supposed to be flushed every so often, but most people never have, and we end up with the brown sludge.

 

^^what he said. dexcool is "ok". problem is,nobody flushes it out,or changes it and it changes to mud. You cant run it forever and think nothing is going to happen. I changed mine to green last year. ive got a little mud on my cap,, im going to flush it again next week actually.

 

Really? Do we have to go through this again? Switching to ethylene glycol, (green) does not cure the problem, it creates a much larger, more expensive one: Water pump failure Flush it out, clean it out, and put Dexcool in it. You're asking for trouble using ethylene glycol, and you'll get it.

 

Is it true that it ruins the gaskets?