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Since it is the season to test the antifreeze in your equipment and vehicles, this may be the time to talk about this?

Hopefully, there are some chemists, or people who know, that will chime in here.

All manufacturers say you should clean, flush and refill your cooling system about every five years.

Why? What goes bad in antifreeze? Can the pH and nitrates be adjusted with the addition of new additives?

Explain green, orange and red antifreeze as well as oat and hoat coolant.

I see Ford diesels recommend an SCA, (Supplemental Coolant Additives) be added if needed after testing with a test strip.

Ford sells bottles of the SCA as well as Wix, Prestone, Amzoil and many others.

These additives help keep wet sleeves intact from electrolysis and stops rust and corrosion.

Then there is Evans Waterless Lifetime Coolant, at about $50/gallon that solves all these problems.

Endorsed by Jay Lenno, who has rather deep pockets.

Hopefully those in the know can chime in here to help educate us as to what goes wrong, and why?

If we can easily fix this, with a bottle of the correct juice, to stop issues in the high priced equipment, that may save us all money.

Educate us, PLEASE!




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21 minutes ago, lorenzo said:

Miraculously our fathers and grandfathers somehow got along with just plain old antifreeze.

Ya ever see the gobs and piles of rust in say an M block?  You won’t find that in newer engines that have always run coolant with adequate anti corrosion additives. All that rust hurts heat transfer and can block passages. 

It is additives that keep the 400 series IH engines from pin holing the sleeves in a few thousand  hours due to cavitation. I used to have in my possession an old diesel engineering text book that did a pretty good job of explaining that whole cavitation thing, and what the exact chemical was that prevented it. Copyright 1969. Sadly it has been misplaced. 

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Oh boy........time for coolant wars lol.  

What I know:

  #1 color doesnt really mean anything.  Can vary between manufacturers, usually a different color is an indication that's it's not conventional ethylene glycol, but the FleetCharge coolant Peak sells is pink, and is merely SCA precharged conventional coolant so gotta be careful.  

#2 Most modern EGR engines want OAT nitrite free (which we all know is the normal SCA additive) coolant due to the very high temperatures in the EGR cooler cores and conventional cant handle it.  This is "extended life" and has that 5 year maintenance free guarantee.  OAT also has better heat transfer properties.

#3 Hybrid OAT is a blend of the 2 for I guess the best of both worlds and has a bit better corrosion protection than OAT.  I never really used it in anything.

One question I have, is how reverse compatible is extended life OAT coolant in older stuff?  I've heard that it doesnt play well with copper/brass soldered radiators and is meant more for modern aluminum/plastic cooling packages.  

Given the fact NOBODY checks SCA levels in coolant, always felt going to extended life across the board would be a better move for most.  Someone can correct me if I'm wrong.  

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I don't know much about new diesels but will address old school antifreeze. I have a chemical engineering degree but have never studied antifreeze and engine corrosion much.

Antifreeze don't go bad. It will continue to protect your engine from freezing if the strength is maintained. It is not even necessary if you live in a tropical climate. Ethylene glycol is the main component in traditional antifreeze. 

However antifreeze contains corrosion and deposition inhibitors. These inhibitors get used up and need to be replaced or replenished. Sca is (was?) A common inhibitor for diesels.

Corrosion/deposition is a complicated subject i have some experience with. In industrial applications they usually install metal coupons to monitor and adjust their chemistry as needed. A sleeve failure seems bad to us. However we had a  recovery boiler failure at the paper mill where I worked that could have been deadly and was crazy expensive. It was due to deposits not corrosion. 

I still have a book on water treatment. Its like a thousand pages.


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I watched a YouTube on the Ford diesels and antifreeze.

Ford has many variations for the different engines and antifreeze.

They recommended the green be changed every 15,000 miles and the new HOAT up to 60,000 miles.

Making sure all the old stuff is totally removed before changing from one to another or the change will cause troubles.

What I was basically looking for was a test strip to tell us where the antifreeze is currently at.

Then to tell us how to treat it so we do not over-treat, or under-treat with SCA.

Both are dangerous.

With the IH engines eating holes in the sleeves, this is a huge thing.

Antifreeze is far from simple anymore.

We apparently need to be junior chemists to keep our equipment running and out of the shop.


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Used these for nearly 30 years. Should be available at any CaseIH dealership or truck shop. Dip the test strip in your coolant & line up the colors on the test strips to give you the SCA level in your coolant. 



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