Guys…I stumbled upon this quote in a website (actually a legal website run by someone who plans on suing GM):

"Customers complain that DEX-COOL forms a sludge-like substance that clogs their vehicles' cooling systems causing them to overheat, and that DEX-COOL corrodes all parts of the engine it comes in contact with including the heater core, water pump, hoses, cap, upper and lower intake manifold gaskets, thermostat, and engine block".

My question though is simple: it’s time to buy a coolant for a brand new radiator on my stock 98 Z28. Should I buy Prestone, or Dexcool as recommended in the GM user manual??...Cos where I live the weather goes up to 113F & it's very humid at day's peak. Or does GM say Dexcool in order to make some money?? Thanx guys.

 

DexCool is fine. I've been using that in all of my GM cars for years and have never had a problem. You can sue anyone for anything these days, so it wouldn't surprise me if that guy had no idea what he was talking about.

Mike

 

Do a search. This has been covered many times.

 

I heard that it corodes in iron blocks and steel componets, but the risk is GREATLY reduced with the aluminum LS1. I do know it is rough on the hoses, but overall, the amount of damage it could do to your engine is comparable to a 2 year old in a boxing match compared to what milage and driving does to it.

You engine will surely die before DEXCOOL can do any noticible harm. It is prefered because its thermal properties are much better than traditional coolant, and it only sludges up when you mix regular coolant with it.

 

Incorrect.

Both Dexcool and conventional antifreeze are ethelyne glycol based. It WILL NOT SLUDGE FROM MIXING THE 2! I've done it w/out a prob. I even ran stop leak with it w/out a prob. Even the MANUFACTURER says you can mix them. All it does is reduce the supposed 150k mile lifespan.

Dexcool just has a better additive package. Lubes, better anti-corrosion agents, etc. GM runs Dexcool in IRON blocked engines w/out a prob.

Rough on hoses? I wonder why our Grand Am and some friend's pickups still have the original hoses with over 150k miles on them if its hard on hoses.

The bottom line. Dexcool was new so it got the blame for a plethora of problems that are truely related to poor engineering, mechanics, or GM's use of inferior materials.

 

Sludge has occurred in some dexcool equipped vehicles due to a variety of contaminents - adding dirty water to it, etc. Some said the problem was due to too much additive from the factory. My 96 impala had the problem and when I showed the service manager the TSB they flushed the system for free even though the car had 50K miles on it. After they flushed and refilled with dexcool I never had the problem again - 75k later it was still clear.

Bottom line - they have been using it for more than 10 years and I know of very few problems in the F-Body community, so I wouldn't worry about it, the dexcool will be fine.

 

Hmm.. Well I'm definately no expert, all the info I gave I learned from a dude at the GM shop. I had my dad mix regular coolant with my DEX in my old 3.4L and the gm guy said thats what caused me to need to buy a new cooling system....

Yeah as far as the hoses, I did say they would outlast the life of the car. I'm just saying that compared to conventional coolant, its more damaging.

But i dont have any conclusive evidence, thats just what i was told from a GM tech.