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Anti freeze: orange, gold or green

Dear Tom and Ray.

I have a 2005 Ford F350 diesel pickup truck. I am in the process of bringing it from cold Massachusetts to very hot South Terxas.

My brother is driving the pickup the first leg of the trip–from Boston to Lexington Kentucky.

He got an oil change at a local Ford dealer and they told him the truck needs gold anti freeze.

The anti freeze that is in the truck now is green. It was put in at another Ford dealer when they replaced a broken head gasket 2 years ago.

I have been researching this question and all the information I find has not cleared anything up.

What should I do? Leave the green antifreeze in or change to gold? Please keep in mind this is a diesel truck, and also the heat difference between South Texas and Massachusetts.


Here’s what the brothers have to say about coolants. and I concur.


Tester’s link is correct and helpful. But you should also be aware that there are two families of coolants in use – Propylene Glycol and Ethylene Glycol. (There are probably a few people who still use ethyl alcohol, but it was largely replaced by more permanent Ethylene Glycol based coolants about five decades ago). There’s not a lot of difference between the two, but they do have slightly different properties and engineers may prefer one or the other depending on what problem they are trying to solve. Propylene Glycol is considerably less toxic than Ethylene Glycol and is sometimes preferred for that reason. I’d avoid mixing the two if only to avoid arguments with mechanics who probably know less about coolant than you do by now.

You should also be aware that OAT coolants are somewhat controversial – especially something used by GM called DEX-COOL that apparently damaged some cooling systems.

You might want to read the Wikipedia article on Antifreeze

If it has green in it now, I’d leave it there and continue to add green. With the green, ethylene glycol-based coolant, you should have it flushed or at least drained and refilled annually. This is normal. Don’t mix different kinds of coolants as a rule. Long term, mixing them can damage your cooling system.

As a side note, they even use the much less toxic propylene glycol as a food additive in some cases. Look at your salad dressing bottle next time you’re bored!

I don’t like going on color. Your owner’s manual should tell you exactly what to use. You can check the chemicals in it on the manufacturer’s web site and find other products with the same chemicals. Or just buy the exact replacement fluid recommended by Ford.