Its sad to say I'm at a point where I might have to get rid of m Monte if no one can figure out what the problem is. I have a 2005 super charged Monte carlo ss. Back in June or July I had to get a whole new radiator because there was some orangeish brown colored stuff that plugged up the radiator. I can on describe it as a rough grainy playdo. Well since they replaced the radiator and flushed they system, they said they were still getting small chunks but the majority was gone. I have flushed it myself once a month because the mechanic told me too to help get the wrest out. Well I haven't flushed it since mid October. The flush was clean, so I poured dex-cool in it, as the manual calls for. And now Thursday the car started over heating again took it back to the shop. Well now there is a thick blackish brown substance almost like mud starting to clog up radiator. The mechanic has no idea what the stuff is or why its coming back. So does anyone have any ideas? I can't be spending 600-800 every 5-6 months for a new radiator.

 

Wow that sucks.
Try switching to Prestone 50/50, i had an orangey substance in the coolant reservoir, and once switching to prestone it went away, now i dont know if that's what you are talking about, if not i apologize.
Hopefully some other experience members can chime in.

 

Dex-cool is junk. Switch to 50-50. Flush the system and do the switch. Also replace you T-stat, if you haven't done so already. That gunk may damage it and they are cheap enough, just for cya.

 

What do you guys mean 50/50? The dex-cool was 50/50 at least that's what the jug says? Should the fluid just be green?

 

the dexcool is the cause of the sludge, looks like clay, dexcool can not be mixed with any others coolants, even if it says mixes with all colors don't believe it.
Flush and don't put dexcool in again.
then flush again and don't put dexcool in again.
then flush again and don't put dexcool in again.

http://consumeraffairs.com/news04/20...m_dexcool.html

it will take a few flushed to get it all out, and never put dexcool in again.

 

if all that flushing doesnt help and you have electric fan. what i did when i had my 86 firebird and the relay went out was install a toggle switch. my cool mechanic did it for only 35 dollars and it was a 10 minute work. that coulld help when the car is at a stop or something. cant really help ya on the radiator case bcuz im not that expirienced in them

 

And never put Dexcool in again!

 

yeah its the Dexcool flush it out & use somthing else

 

did you guys not read the article?! if your car ever starts to have the problems they were having, it wont help you trying to get money back from GM by changing your coolant.

 

Leave Dex Cool alone...it is bad news. The first thing I did was flush that stuff out of my Monte when I got it. Get yourself 2 bottles of Prestone or Peak (full strength) and a new thermostat. Flush out the radiator, the block, overflow container and the heater lines really well. Add coolant and burp it out and you should be good.

The dex cool has "stop leak" in it and the sludge you are describing is just that.