I was told there are problems with Dex-Cool. It may eat aluminum and ultimately cause damage to the engine and other components? I'm considering goint to AMsoil compatible coolant. What do you think?

 

Well, here's what the owner's manual says about it.

Engine Coolant
The cooling system in your vehicle is filled with
DEX-COOL® engine coolant. This coolant is designed
to remain in your vehicle for five years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX-COOL® extended life coolant.
The following explains your cooling system and how to
add coolant when it is low. If you have a problem
with engine overheating, see Engine Overheating on
page 5-25.
5-22
A 50/50 mixture of clean, drinkable water and
DEX-COOL® coolant will:
• Give freezing protection down to −34°F (−37°C).
• Give boiling protection up to 265°F (129°C).
• Protect against rust and corrosion.
• Help keep the proper engine temperature.
• Let the warning lights and gages work as
they should.
Notice: Using coolant other than DEX-COOL® may
cause premature engine, heater core or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs first. Any repairs
would not be covered by your warranty. Always use
DEX-COOL® (silicate-free) coolant in your vehicle.

Doesn't sound like a good idea to change to another coolant.

 

There have been problems with Dexcool...in fact, I believe GM is having to defend damage lawsuits.

Try typing "Dexcool" in your browser window for all the DIRT. It has to do with air constantly being admitted to the cooling system when the engine cools...the coolant has degraded into muck in some peoples vehicles and ruined the cooling systems. I believe that it will also attack non-compatible seals in the cooling system resulting in leaks and subsequent overheating if you don't keep a close eye on your coolant level. In its virgin state, I highly doubt that it is incompatible with aluminum, but that may change when it is degraded.

I personally tried Dexcool in my wife's Avalon for the scale and deposit inhibitor package and for extended coolant life. It attacked the o-ring seal on a block drain leading to a constant drip leak that was not visible under the car...the car kept overheating and I couldn't keep the coolant level up. Exasperated, I finally gave it up and changed back to Toyota's coolant, which I later learned is a superior HOAT (don't ask me what it means) formulation. During the change out, I discovered the leaking block drain, which explained why the car was overheating. No more coolant loss and overheating. I did not experience the problems of muck forming in the cooling system.

Since GM continues to resolutely use the Dexcool as factory fill, perhaps they have identified and fixed the related problems, and made their cooling systems fully compatible with Dexcool. I am not sure AMSoil coolant would be my choice...I believe Zerex offers an HOAT formulation. This will be a question I will have to answer for myself when my C6 arrives...I know the Dexcool will NOT be replaced in kind when maintenance is due.

 

Hmm..Makes ya Think..

 

Makes you think what? Go over to the C5 forum and ask about Dex-Cool problems. Mostly nada. Keep you overflow container at the recommended level and it'll be good to go. I've had it in mine for 7 years without problem.

Don't Listen to Urban legions, it is a waste of time. There are real issues out there.

 

A very important thing to consider, Dexcool uses a different chemistry than older ethylene glycol coolants. Don't ever mix them. Even in very small quantities, very adverse chemical reactions can occur.

Dexcool offers superior aluminum corrosion protection while eliminating the sludge formation problems of coolants which contain silicates. Our cars were designed to use Dexcool, and the seals were selected to be compatible with it. Any use of older ethylene glycol formulations in our cars can lead to serious problems. Similarly, use of Dexcool in cars not originally designed to use Dexcool can create serious problems.

 

Stay the course. Keep what ya Got. Right Mr Dog?

 

I think you mean "urban legends"...pesky little malapropisms.

It wouldn't hurt us to be better informed about coolants. Here is a basic article from Motor Age that discusses the different types:http://www.motorage.com/motorage/art....jsp?id=156227

Amsoil's coolant is propylene glycol (not covered in the article)...the best thing going for it is it has less environmental issues than ethylene glycol. I definitely would NOT use this in my new Corvette, nor would I use the old ethylene glycol (IAT, inorganic additive technology).

I can't argue with sticking with Dexcool if Corvette owners are having no complaints. I also agree, and found out the hard way, that you should not try to use Dexcool in cooling systems that were never designed for it. The article cites a case where adding Dexcool to a Ford cooling system led to cavitation corrosion of the pump impeller (not an urban legend). I will consider a hybrid organic additive technology (HOAT) formula for my Corvette when it's time for replacement...Mercedes has been using it for thirty years; Toyota uses it, Ford and Chrysler use it.

The article says that even with ethylene glycol coolants, the silicates have been reduced to like 250 parts/million. Even before that, I never had any problem with silicate scale formation in my radiators...the big issue is that change intervals have to be maintained.

 

They used to have a label in the engine compartment that said the above.

 

My C5 has 4 years and 61,000 miles on Dexcool with no problems. When I replaced the original fill, I used distilled water for the mix.

 

This same issue came up in the early C5 days. The short version of the outcome was to keep the overflow bottle topped off as mentioned above to eliminate the extra air in the system. Stay with the Dexcool and keep it full. You can buy Havoline/Texaco Dexcool at Walmart for a lot less than at your dealership.

 

My Dex-Cool is leaking..Got Home tonight and started to come out...From under the Fill Bottle..Wonder if it has a hole or something cant really tell cant see in the dark that great...

 

No urban legend, Dex-cool instability was an infrequent but real problem that has since been fixed. My '97 GMC used Dex-cool and was fine until it was close to exactly 5 years old in 2002, when it rapidly turned into brown sludge. Our small town GM dealer had never seen the problem before, but now 3 years later they know all about it. Turns out, the early formulation of Dex-cool was marginally unstable and subject to spontaneous decomposition. All Dex-cool has since been reformulated and will not have that problem again. I didn't find out how many years ago that formula change occurred.