Originally Posted by offroadbrigade

They started using different colors when rads went aluminum some of the antifreeze companys had corrosive chemicals against aluminum that's why now a days there is so many universal dyes

Originally Posted by MudHippy

Not so. Think about it. Aluminum heads have been commonplace on engines for probably longer than you've been alive(longer than I have atleast, and I'll be 37 in about a month). And fancy colored(not green) anti-freeze didn't show up until the mid-90's. So what kind of sense does that make? Don't answer that...please(just a rhetorical). In fact, the newer non green/silicate-free or low silicate anti-freezes offer LESS immediate protection for aluminum engine parts(including radiators). Which is part of the debate on whether or not to use ANY non green/silicate-free or low silicate coolants in engines that have aluminum components in contact with the anti-freeze/coolant. In short, silicates provide immediate protection to aluminum, where as coolants that don't have any(or very little) silicates have to be used for a period of time before establishing a protective coating/layer on aluminum surfaces. Only after which do they become effective in protecting aluminum.

Since you obviously didn't check the link I provided, which explains when and why the changes were actually made, let me quote it for you.

COOLANT, CHEMISTRY, AND CORROSION

• Water
• Ethylene Glycol
• Silicates
• Organic Acid Technology
• Propylene Glycol
• Waterless Coolants
• Coolant Additives

Plain Water is an excellent coolant (think swimming pool). Naturally occurring, abundantly available and mixes with almost anything. It can be pumped, filtered, heated, cooled, evaporated, condensed and stored. Essential for plant and animal life and the most widely used of all solvents, even though it is a great automotive coolant, it is not without a few draw backs:

• First, it has a tendency to freeze at 0C` (32F`). Not considered a desired trait since during freezing, expansion occurs and thick metal castings can be rendered useless. If this does occur, hopefully the freeze plugs allow enough expansion relief.
• Second, water will boil at 100C` (212F`). This is definitely not desired. As the water boils, interruption to coolant flow occurs, the steam vapor displaces the liquid capacity, further reducing efficiency.
• Third, plain water will allow corrosion to occur on dissimilar metals, and deterioration to accelerate. The best way to insure your self of expensive cooling system repairs is to fill with plain water only!

Ethylene Glycol A colorless syrupy alcohol, HOCH2CH2OH, used as an antifreeze in cooling and heating systems.1 Mixed with water at 50%, it is found in almost all automotive coolants, and is the backbone of (almost) all coolant chemistry. Ethylene Glycol (EG) has very important characteristics that tailor the coolant mix to the automotive application. The current thinking for automotive coolant is to dilute water with enough ethylene glycol and corrosion inhibitors to change the poor characteristics of water, while retaining the good ones. The primary additives are Ethylene Glycol and Di Ethylene Glycol for freeze/boil protection. The corrosion inhibitors used vary widely by manufacture, and by vehicle requirements. The reason for so many different coolants lies in the complexity of the inhibitors used.










Silicates are deemed to be abrasive in a cooling system, and are blamed for premature water pump seal failure. With the average miles per year per car on the rise, it does seem to be a valid concern. But is it worth the price of a dex-cool clean up? If your water pump is timing belt driven, the water pump may be replaced at 60,000 or 90,000 miles anyway.

Organic Acid Technology or OAT's are coolants that are formulated without the use of silicates. Since silicates have a short life, removing them allows a longer service life. Typically, coolants advertised as 5 year, long life , extended life or Dex-cool are examples of OAT's. Common components to OAT coolants are Carboxylate, sebacate, and 2-ethylhexanoic acid (2-EHA), which are corrosion inhibitors, used instead of silicates. Depending on which manufacturer is filling the jug, the inhibitors may change. Dex-cool uses 2-EHA which among other things is a plasticizer which has the effect of softening plastic. GM intake manifolds are made of plastic........... If it is found that Dex-cool is dissolving the gasket material, it will validate what some folks have been saying for a long time: Dex-cool eats gaskets. We'll see. Prestone doesn't use 2-EHA in it's long life coolant, instead uses carboxylate.

As long as the cooling system is in good shape and the chemistry is balanced, these coolants have demonstrated that in fact they can go longer that their predecessors. However, when the balance is upset, either by improper filling procedures or weak concentrations or improper manufacturing, the OAT can come apart, causing thousands of dollars in repair bills. GM's Dex-cool is a huge problem on some vehicles. Class action suit pending.....

Originally Posted by fdp101452

I couldnt get the color chart to work, but great info, thanks Mudhippy

Originally Posted by kuzbro

I have a 90 truck that has always been cooled with Toyota Red.