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DEX-COOL Extended Life Anti-Freeze/Coolant. By Scott Mueller http://www.theherd.com/articles/dex_cool.html

A revolutionary new type of long life engine coolant is now being used in ALL '96 GM cars and trucks except for Geo and Saturn. It is called Dex-Cool, and can be distinguished by it's unique orange color. Dex-Cool is manufactured for GM by Texaco Havoline, and is rated to last 100,000 miles or 5 years, whichever comes first.

Dex-Cool is an Ethylene Glycol based high performance coolant that contains unique corrosion inhibitors, which are different from anything else on the market. Dex-Cool is vastly superior to conventional coolants, which use silicates, phosphates, borates, nitrites, nitrates, and amine additives to eliminate corrosion. These additives are abrasive to water pump seals, and silicates are especially unstable and drop out of solution and form a gel after time. All of these conventional inhibitors deplete after a short time, which is why conventional coolant must be changed every year.

The unique corrosion inhibitor technology in Dex-Cool is based on the use of two organic acids, which are synergistic and combine to form carboxylates. Texaco refers to this as Organic Acid Technology (OAT), or Carboxylate Technology. The corrosion inhibitors used in Dex-Cool deplete very slowly thus eliminating the need for traditional additives, or frequent change intervals.

Note that contrary to what some may say (or write), you can indeed mix Dex-Cool and conventional coolant with no ill effects. However, if there is more than 10% of conventional coolant in the system this will reduce the concentration of the Carboxylate such that conventional coolants change intervals must be followed. In other words, if you mix it, you can't leave it in for 100,000 miles or 6 years, but instead should treat a mix just like conventional coolant and change it every year until the concentration of Dex-Cool is over 90%.

You can purchase Dex-Cool in gallons two ways, either under the GM part number (#12346290) which lists for $15.95 (about $10 with a discount), or under the Texaco-Havoline brand name at your local parts store. In my area, Pep Boys has it for $7.49. Currently in my area they are about the only place that has it, as it is still fairly new on the market.

Dex-Cool is extremely impressive compared to anything else currently available. Personally I am converting ALL of my vehicles over to Dex-Cool. For the Impala, I even installed the '96 Dex-Cool labeled reservoir cap and Dex-Cool "Notice" sticker for the radiator cover, exactly as they come on the '96 Impala. The Dex-Cool reservoir cap is available under #10285918 and cost me $3.29. The cap is functionally the same as the cap used in the '94 and '95 cars except for the sticker on the top which says to use only Dex-Cool, and which also has an orange dot in the middle instead of the green one found on the earlier caps. The Dex-Cool "Notice" sticker, which goes on the radiator cover, is available under #10283878. I don't know what it cost as my dealer did not charge me for it.

Since Dex-Cool is an Ethylene Glycol based coolant, it has the same excellent anti-freeze and heat transfer capabilities of other standard Ethylene Glycol based coolants. As such, Dex-Cool will perform as follows, which is identical to any other Ethylene Glycol based anti-freeze/Coolant:

Mixture (coolant/water) Freeze Point Boil Point 50/50 -34 deg F 265 deg F 60/40 -62 deg F 270 deg F 70/30 -84 deg F 276 deg F

Mixtures of less than 50% coolant or more than 70% coolant are not recommended. Note that these temperatures are in degrees Fahrenheit, and the boiling point temperature is dependent on a sealed cooling system with a 15 psi rated pressure cap.

Note that Dex-Cool differs from conventional coolants only in the additive package, not in the Ethylene Glycol base, meaning it provides the same anti-freeze and boil over protection as conventional high performance coolants, but also provides superior corrosion protection to all cooling system metals.

This higher level of performance is unlike coolants based on Propylene Glycol (i.e. Sierra brand), which are advertised as being environmentally more friendly than standard coolants, however which are also inferior when it comes to thermal transfer, anti-freeze and boil over capabilities. For example, Propylene Glycol based coolants freeze at -26 degrees Fahrenheit in a 50/50 mixture, compared to -34 degrees for the same mixture of Ethylene Glycol coolant. Also, despite their "green" claims, Propylene Glycol based coolant is indeed poisonous to humans and animals. GM reluctantly agrees that Propylene Glycol based coolants can be used in pre-'96 vehicles, stating that it will perform "adequately", but other manufacturers such as Chrysler indicate that the use of Propylene Glycol coolants are prohibited, and may void the warranty.

Due to the reduced thermal performance and conventional corrosion inhibitor packages, I do not recommend Sierra or any other Propylene Glycol based coolants. Since Dex-Cool is based on a superior Ethylene Glycol base, and all auto manufacturers specify Ethylene Glycol based coolant as recommended for their cooling systems, Dex-Cool can be used without problems in any automotive cooling system.

It might be difficult for some people to get excited about something like engine coolant , but Dex-Cool is the first revolutionary new product in this area in quite some time. In the future, Texaco Havoline expects other manufacturers to follow GM's lead and also switch to Dex-Cool for new vehicle factory fill.

Warning

Dexcool is a formulated antifreeze/coolant used in over thirty-four million vehicles sold by General Motors. Used by GM since 1996 in most car and light truck models, Dexcool is manufactured and distributed by ChevronTexaco, Equilon and ChevronTexaco Global Lubricants.

Although Dexcool is marketed to last 5 years or 150,000 miles, consumers say the product is defective and damages vehicles. According to reports, Dexcool has been linked to corroded and clogged radiators and radiator caps, eroded water pumps, rotten radiator hoses, leaky cooling system gaskets, chronic overheating and engine damage.

Consumer Affiars article

GM Owners Still Steaming Over Dex-Cool Corrosion, Engine Damage Blamed on Coolant

By Joe Benton ConsumerAffairs.Com August 29, 2006

Dex-Cool

• GM Owners Still Steaming Over Dex-Cool • Consumer Complaints Ten years after General Motors began using Dex-Cool as an antifreeze in most of its cars and light trucks, GM car and truck owners continue to complain that the coolant corrodes and clogs radiators and radiator caps, erodes water pumps, rots radiator hoses, causes chronic overheating and engine damage while leading to leaky engine gaskets.

Patricia in Barberton, Ohio, feels cheated by the automaker. "I have had 2 intake gaskets replaced on my 1997 Pontiac Grand Am. The gaskets cost me close to $1,000 and they told me there is no guarantee it won't happen again," she wrote in a complaint to ConsumerAffairs.Com.

"I just recently saw about the Dex-Cool problems and that is what I have been using in my vehicle since that is the kind that is required from the automakers," Patricia said.

Dex-Cool is now used in almost 40 million vehicles sold by GM since 1996. On its website, GM claims Dex-Cool will last 5 years or 150,000 miles but a steady stream of consumers insist the product is defective and has damaged their vehicles.

GM is quick to clarify its confidence in the antifreeze by stating that the GM owner's manual recommended 150,000-mile service interval is not a warranty guarantee. On its website, the company now also warns owners to consult their vehicle "owner's manual for the type of coolant right for your vehicle" and never "mix one type of coolant with the other." Lawsuits Pending

At last count there were 14 lawsuits filed in state and federal courts throughout the country by GM vehicle owners angered over their experience with Dex-Cool.

A Missouri judge may soon grant class-action status to suits in his state -- and that would mean that millions of GM customers could become involved in the lawsuit. The Missouri Supreme Court has declined to hear an appeal from GM challenging class-action certification.

The Missouri suit was filed in April 2003 alleging GM vehicles with Dex-Cool in their cooling systems developed a rusty sludge.

The plaintiffs claim that GM refused to repair their vehicles or pay for the repairs and the lawsuit seeks unspecified damages for breach of warranty under the federal Magnuson-Moss Act and the Missouri Merchandising Practices Act.

Samuel in Bellville, Ohio experienced a similar problem with sludge in the cooling system of his car.

"I have sludge in my coolant caused by Dex-Cool,' he wrote. "GM demands that the coolant be used. So far it's just the gasket that has to be replaced. I will see if further damage was caused," he told ConsumerAffairs.Com. GM Is Mum

GM will not comment on the pending lawsuits but continues to claim that Dex-Cool represents an improvement over traditional coolants. Nevertheless, the automaker has alerted mechanics that vehicles operated for 15,000 to 20,000 miles with low coolant levels "may be susceptible to the formation of a rust like material in the cooling system."

Deborah in Hornell, New York faced similar news from her mechanic when she took her 2002 Buick Century in for a maintenance check. Deborah was told the Dex-Cool needed to be flushed and refilled even though the owner's manual stated the coolant ought to be good for 100,000 miles.

"My car has only 48,000 miles," she wrote. "The Dex-Cool had corroded the engine and the mechanic also advised that the plastic manifold would need to be replaced since the Dex-Cool had literally eaten through it."

Deborah blames the costly repairs on GM because in her view the automaker "installed what they knew as faulty equipment, namely a plastic item in an engine unit and Dex-Cool antifreeze that does not work."

In Madison County, Illinois, a lawsuit claims Dex-Cool "began to turn into sludge which then accumulated in the vehicle's engine cooling system and radiator." Clear As Mud

The bright orange coolant often changes into a muddy colored liquid and when the change occurs automobile mechanics blame Dex-Cool for expensive cooling system flushes, gasket replacements, and even new radiators and heater cores.

"You'll see heater cores leaking. You'll see frost plugs leaking. You'll see water pump failures. You'll see overheating problems. You'll see air conditioners not cooling very good. You'll see transmissions burning up at 100,000 miles if the coolant systems are not working right," said one mechanic who works on GM cars and trucks.

Ronald in Downey, California told ConsumerAffairs.Com the Dex-Cool has almost destroyed the engine in his car. "The product in vehicles coolant systems deteriorates aluminum parts in the engine," Ronald said. "The intake manifold, cylinder heads and timing chain cover are all made out of aluminum. My vehicle needs all these parts replaced."

His problems worsened. "The motor has coolant in the oil and oil in coolant," indicating that the head gasket is leaking. "This is the second time this problem has occurred."

The repairs to his damaged engine have now cost Ronald more than $4,000 "because all the aluminum parts have to be replaced." What To Do

As lawyers continue to collect names for potential class action lawsuits from people claiming Dex-Cool damaged their car or truck, automobile mechanics are advising that if you have Dex-Cool as a coolant in your vehicle, you should not replace it with another form of antifreeze.

If your car or truck came from the factory with Dex-Cool, you should continue to use that coolant both as replacement and to top off the radiator, the mechanics say.

Last but not least, if your car came from the factory with standard "green" antifreeze, don't switch to Dex-Cool.