A mechanic working on my other car (a Saturn) told me that dex-cool was a problem and caused corrosion to gaskets on GM cars. I googled this and sure enough there are 14 lawsuits against GM regarding Dex-cool. C-5 engines are aluminum, which may make a difference one way or another. Has anyone got any tech info or maybe has changed anti-freeze?

Thanks,

 

Actually I heard it was the other way. Cheap GM gaskets caused leaks and Dexcool turns muddy and thick with air leaks.

I think Dexcool is great, but if you ever get a leak, fix it right away.

I have had many cars with Dexcool and only one, with a blown head gasket was a problem. Plus I switched over a Ford Taruas and an Accura.

 

There used to be (still is) a lot of complaining about DEXCOOL with the LT1 motor B-body Impala SS/Caprice cars. That's about the time when DEXCOOL was first being used and GM added tablets to the mix. When air was allowed to enter the cooling system, it sometimes created a clogging muddy mess within the reservoir and heater core. Those motors were of coarse iron blocks and aluminum heads. I had two GM vehicles ('96 Impala SS LT1 and '96 S10 V6) at the time and never experienced the issue. Proper maintenance seemed to be the clue.
I haven't heard any of the same complaints with C5/Z06 LSx based motors. I'm assuming that the tablets were eliminated or the all aluminum motors work better with the DEXCOOl over green.

 

There is no problem with DexCool except in the minds of some mechanics. My wife's 99 Saturn is on its second fill of Dexcool. When the 5 years were up I drained the original fill and it looked like it did the day they put it in the car at the factory. I have had 5 GM cars with Dexcool over the past 11 years with no cooling system problems.

Bill

 

Three Vettes with DEXCOOL and ZERO issues. Had a VW GTI with VW brand of DEXCOOL and NO issues.

BC

 

I want to point a different experience with Dex-Cool than what you have had, however let me quickly point out that Dex-Cool is selective to the cars it wants to sludge.

Both of my vehicles were purchased new, 01 Grand AM & 03 GMC HD. The grand am formed sludge at 25K and a new reservoir was put on with a flush under warranty, at 37K the sludge was back and I replaced the reservoir again and refilled with Prestone yellow no problems to date 80K on the clock. My GMC had 5K and a dirty ring formed around the reservoir and I replaced with Prestone, no problems.

Both these cars had no leaks with no air being introduced to the system. My Vette has 36K w. no problems w/ Dex-Cool and my brothers Malibu has no problems with 70K. I guess I got two weird cases, but me if I were to buy another GM vehicle the Dex-Cool would be replaced before the first tank of gas. Just my opinion.

 

Worked for dealership when all the controversy was going on. Seem
to remember a bulletin for the S10. I remember flushing a lot of coolant
systems like you described and warrantying a lot of radiators. Mainly the Vortec engine family starting in 1996. In the beginning of Dex-Cool I was told that it was found to be less corrosive on aluminum parts in the coolant system and the aluminum engine block than your basic green coolant and that is was why Gm went to it. Down the road somebody realized that Dex-Cool did not react well with Cast Iron and when air was let into the system.(so the story goes). When the Vortec engine family was redesigned in 1999 using the LS1 platform. It had aluminum heads but cast iron block.
They must have reformulated the Dex-Cool or redesigned the coolant system because the muddy murk in the radiator and over flow is not an issue like before it was first introduced. The vortec famiy have added aluminum blocks to there line and no problems here
Had 1997 S10 100k had several flush and fills and warranty radiator from murky mud
Had 2000 silverado 75k never flush or fill,np
had 2003 Tahoe 65k never flush or fill np
have 2005 suburban 55k np
have 2003 vette np
have 2004 z06np
Recommended maintenance is the key to any vehicle
If you wan to be over cautious do more drain and fills, and use somebody else's coolant that does not say dex-cool but make sure there brand says meets or exceeds GM dex-cool. I know i have seen it available in green

 

There are two articles over on the "imcool" web site that were papers presented by GM and Texaco when this was going on. Their findings were low coolant and air introduction into the system. Most of the air introduction was coming from the radiator cap. At one time they had a free video on this subject, I still have that.

I switched all my cars to Dexcool years ago, the ones I still have are fine but I also keep an eye on them (94 Grand Am, 89 Suburban).