Dex-Cool : What Color Does It Turn if Bad?

[Maine Sail]

GM is still using this product in the vehicles to my knowledge.

Just because GM is still using it does not mean it won't cause further problems. They are still using it while at the same time paying out hundreds of millions of dollars in settlements for damage related to Dex-cool.

It would be interesting to see if there is a cause/effect issue that has been covered up.

Unfortunately we'll never know because GM chose to settle instead of taking this to court so we would all finally know what the real issue and answer is. With settlements they avoided lots of potential liability by covering only "named" issues in the settlement. These named issues do not include marine engines BTW..

I think most engine mfg. are using these products.

The two leading brands for reliability Honda and Toyota DO NOT use Dex-Cool and many of the European cars do not use it either.

My engine was still running cool but was developing the all too common Dex-Cool sludge in the HX and engine. I think we'll eventually begin to see more issues especially with engines using copper HX's that are brazed with solder..

Again use what you feel comfortable with. I only post this info so you guys can make your own decisions and hopefully research this a little more beyond what I have said and shown.

I spent a long time talking about this issue with a guy who makes this his profession. He showed me piles and piles of parts he claimed were destroyed by Dex-Cool and a 2007 automobile sitting in his shop that he was converting back to green. This was a car owned by the wife of a guy who had GM / Dex-Cool head gasket failures. Paul even showed me the test strip on that 2007 and it was highly acidic. This car had less than 50k and was less than two years old. Dex-Cool claims 5 years or 150k.... there is NO WAY it should have been that acidic..

One of my problems with Dex-Cool is that it is sooo finicky. It does not like air or systems with low water, it does not like any sort of other antifreeze, it does not like some solders etc. etc.. There are literally millions of vehicles affected by these issues I don't see why marine engines would be immune. Green antifreeze is no panacea, and it needs to be changed on a regular basis, but my engine is still getting switched back..

This was the cleaner of the two ends of my HX. Unfortunately taking a picture into a tube is tough and the other end did not come out as well (to dark). As I said still cooling but for how long..? The sealed side of a cooling system should NOT look like that especially after having been changed with brand name Dex-Cool every two season since new in 2003..

P.S. Subaru ate three sets of head gaskets, at their expense, on my mothers car before finally replacing her antifreeze with a different product. Since that change over no more problems.. Subaru is partially owned GM and they NO LONGER use brand "Dex-Cool" and now, like Honda & Toyota, use a proprietary Subaru antifreeze. On my mothers 1999 it came with a product very similar to Dex-Cool....

 

[robot]

...
P.S. Subaru ate three sets of head gaskets, at their expense, on my mothers car before finally replacing her antifreeze with a different product. Since that change over no more problems.. Subaru is partially owned GM and they NO LONGER use brand "Dex-Cool" and now, like Honda & Toyota, use a proprietary Subaru antifreeze. On my mothers 1999 it came with a product very similar to Dex-Cool....

Sorry for bringing this thread back from the dead... I stumbled upon it while searching for information on Dex-cool.

Just thought I would stop by to say that Subaru has never been a division of GM and they have never used Dex-Cool in any of their vehicles. For a few years GM owned about 15% of Subaru but they sold it to Toyota a long time ago.

It is quite strange that your Subaru dealer decided to remove the factory coolant and use Dex-Cool instead. I'm not sure how long it has been around but Subaru does now offer an OAT (organic acid technology) coolant similar to Dex and all other extended life coolants.

If you want to avoid 2 ethyl hexanoic acid (2-EHA) (the controversial ingredient found in Dex and Dex-clones) Peak Global Lifetime is a safe bet. G-05 is good as well but it is becoming hard to find.

 

[Maine Sail]

Just thought I would stop by to say that Subaru has never been a division of GM and they have never used Dex-Cool in any of their vehicles. For a few years GM owned about 15% of Subaru but they sold it to Toyota a long time ago.

This is correct GM sold it's 20% stake in Suburu/Fuji Heavy Ind. in about 2005 but when my mother purchased her car in 1999 GM still had a big stake. The anti-freeze in her car, according to her dealer, was basically the same as Dex-Cool. Suburu supposedly changed the formulation and has a different additive package now. Either way the dealer switched the antifreeze it came from the factory with after her multiple head gasket failures and to this day, since the switch, she has had no more head gasket failures. Maybe coincidence you never know..

 

[robot]

The anti-freeze in her car, according to her dealer, was basically the same as Dex-Cool. Suburu supposedly changed the formulation and has a different additive package now. Either way the dealer switched the antifreeze it came from the factory with after her multiple head gasket failures and to this day, since the switch, she has had no more head gasket failures. Maybe coincidence you never know..

Don't get me wrong, I have nothing good to say about Dex-cool, but I think the two subsequent failures were either due to installation error, warped heads (heads should always be checked for flatness after removal), or a cracked head.

Some models of the 2.5L engine are very prone to head gasket failure. To address this issue Subaru updated the head gasket and made available a little bottle of "Cooling System Conditioner". Repeat failures are not very common.

In my Subaru I use a low silicate "good old green" and the cooling system conditioner.

 

[kloudie1]

Dex Cool Results

Had to replace the radiator in the car because the stuff degraded into a flaky black mess that plugged passages ..

 

[catsailor]

G-05 is the primary factory fill for Ford and Chrysler and....

Sorry for bringing this thread back from the dead... I stumbled upon it while searching for information on Dex-cool.

Just thought I would stop by to say that Subaru has never been a division of GM and they have never used Dex-Cool in any of their vehicles. For a few years GM owned about 15% of Subaru but they sold it to Toyota a long time ago.

It is quite strange that your Subaru dealer decided to remove the factory coolant and use Dex-Cool instead. I'm not sure how long it has been around but Subaru does now offer an OAT (organic acid technology) coolant similar to Dex and all other extended life coolants.

If you want to avoid 2 ethyl hexanoic acid (2-EHA) (the controversial ingredient found in Dex and Dex-clones) Peak Global Lifetime is a safe bet. G-05 is good as well but it is becoming hard to find.

can be easily found as Ford "Premium Gold". It is a hybrid, both OAT and more conventional inorganic chemistry.

Another issue that boat owners need to be aware of is electrolysis, but not in exactly the manner we normally think of. Circulating electrolytes (coolant) can easily generate a current. This is often implicated in black coolants (orange = oxidation, black = reduction). Check for ANY voltage between the engine and the heat exchanger fluid. Conductive hoses can be a problem.