FlyFast

I just changed the dex-cool in my 2001 yukon with just over 100k. The dex- cool looked very dirty like muddy water. I refilled the system with clean distilled water ran the truck and then drained the system again. I refilled with the old green prestone and distilled water, now the temp guage takes longer to warm up or so it seems.

Are you guys going back to dex-cool after 100K? I feel better having the mud out of my motor? What do you guys think of the dex-cool coolant vs the old stuff?

Thanks

FOUNTAINATLAST

Dex-cool is junk once it gets some miles on it, like you said turns to mud. Mixing the old with the new is not good though, the two have different additives and when mixed it hard on the seals. You can change just make sure you completely flush out all the old dex-cool first.

Airpacker

The inside joke trade name for Dex cool is actually WRECKS COOL! I have seen more corroded aluminum sealing surfaces since that crap came along than ever before. Flush the hell out of it, resevoir bottle included and replace with god old green coolant.

phughes69

When I used to work at the GM milford proving grounds, we called it Dex A clog.
My 96 diesel has it in it and from what I have learned about it is that the cooling system can not have air in it. If air mixes with Dex a cool it will cause corrosion to aluminum.

Strip Poker 388

iTrader: (6)

thats real good

Are they still selling it???

Hydrocruiser

No Dex cool for me..

http://www.cwcd.com/CM/ClassActions/ClassActions35.asp

Superboat Guy

Great a class action, we can get a coupon for $5.00 off on our next new GM car and some lawyers will make millions

d1mbu1b

my 1998 GMC truck 5.0 vortec using dex cool has been a problem since I baugt it used.
The coolent had been replaced with regular anti-freeze (green)
The first thing to go was the coolent hose connector/nipple in the intake. It was made out of some composite plastic that looked like metal. I was told the regular green antifreeze ruined it. replaced it with a real metal nipple.
The second thing to go was the plastic intake manifold gasket. I was told the green stuff ate that too. It was destroyed arouind all water passaged.

I found this problem because I was having the infamous cold start piston slap. I tore it down and realized it was just coolent in a lifter.

I replaced the gasket and went back to dex-cool. It has run problem free since then 2-3 years so far.

My point is you may want to reconsider using regular anti freeze in a dex-cool engine.
But you never know the dex cool could have ruined them before hand and now im just starting the process all over.

Poorsche

Is it just dex-cool that's the problem or is it all Orange coolants?

Wally

iTrader: (1)

You sure you dodnt have the 5.7??

the intake leak you had is a very common problem on the 5.7's do a search on the truck forums and you will see it has nothing to do with the green antifreeze but with the gasket being installed wrong at the factory and the manifold not being torqued down correctly.

That coolant hose connector is also a POS straight from the factory...they break with very little stress. I have no idea why they even went with it in the first place.....i too broke one on my 96 suburban when installing a heater core bypass for my A/C system.....changed it out with a stainless one.

And the piston slap is very common on the gm trucks.....theres two ways of combattig it. First is to get the carbon cleaned off the piston tops and combustion chambers. Sea-foam seams to be the choice of most to do this. Second it seams that many guys are having the ECM custom programmed to get rid of it as well. I know on the new body style trucks with the 6.0's there was a re-flash program that GM came out with to try and get rid of the piston slap....it worked for some and not for others....