# Car engine coolant--types **URL:** \ **Category:** In My Humble Opinion\ **Created:** [May 4, 2017, 9:45pm UTC](https://boards.straightdope.com/t/car-engine-coolant-types/785874 "2017-05-04T21:45:27Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Flyer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/flyer/32/7298_2.png) [@Flyer](https://boards.straightdope.com/u/Flyer)\ **Post date:** [May 4, 2017, 9:45pm UTC](https://boards.straightdope.com/t/car-engine-coolant-types/785874/1 "2017-05-04T21:45:27Z")
If you check the owner’s manual of every car made in the last 20 years or so, it screams to high heaven that there is ONLY ONE!!! proper kind of coolant to use. This is accompanied by almost-Lovecraftian warnings of doom and severe damage if you use any other type of coolant. On the other hand, go to Walmart or any auto-parts store, and every major manufacturer of coolant (including the private labels, such as Walmart’s brand) claim that their product will work in any engine, with any type or color of coolant. This claim is consistent across all price levels. So which is correct, or at least closer to being correct? ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [May 4, 2017, 10:23pm UTC](https://boards.straightdope.com/t/car-engine-coolant-types/785874/2 "2017-05-04T22:23:58Z")
I’m no help. Of all the cars I own, the _newest_ is over 20 years old, and I’ve _never_ read an owner’s manual. 😃 ---
**Author:** ![DorkVader](https://avatars.discourse-cdn.com/v4/letter/d/73ab20/32.png) [@DorkVader](https://boards.straightdope.com/u/DorkVader)\ **Post date:** [May 4, 2017, 10:33pm UTC](https://boards.straightdope.com/t/car-engine-coolant-types/785874/3 "2017-05-04T22:33:57Z")
Just guessing here, but your owners manual giving you such dire warnings about using the wrong coolant also says to use a coolant made or sold by Ford/Cheverolet/GMC/Toyota/Volkswagon or whatever brand car right? I’ve seen this a lot with Fords and transmission fluid, but I’ve never seen coolant warnings. Might be because I’m not looking though. Bout the only thing I use the owners manual for is to figure out how to set the clock twice a year. Its a marketing ploy. Sort of like how (again Ford is the one I’ve noticed) you never see a car commercial mention mechanic’s services provided by anyone but, very specifically, the service department at the dealership. Except Cadillac and their motor oil, forgot about them and their motor oil, I’ve never had a caddy, but I seem to recall something about voiding warranties and motor oil in connection to Cadillac. ---
**Author:** ![Weisshund](https://avatars.discourse-cdn.com/v4/letter/w/ba8739/32.png) [@Weisshund](https://boards.straightdope.com/u/Weisshund)\ **Post date:** [May 4, 2017, 10:39pm UTC](https://boards.straightdope.com/t/car-engine-coolant-types/785874/4 "2017-05-04T22:39:37Z")
Orange organic can ONLY go in an aluminum radiator, it does not have silicate for anti rust, some organic acid crap. it EATS copper and turns sludgy Green and Yellow are ethylene glycol, with silicate anti rust additives. DO NOT mix the orange koolaide with the other kinds!!! If you flush the system, ANY system, you can refill any of them with standard green/yellow antifreeze on sale every place. Also not all of the orange stuff is intermixable, easier to flush and refill with standard. Antifreeze never wears out, its the anti rust additives that do ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [May 5, 2017, 7:29am UTC](https://boards.straightdope.com/t/car-engine-coolant-types/785874/5 "2017-05-05T07:29:32Z")
When I thought about it a couple of years ago, I decided that Orange and Green coolants /could/ be mixed together, based on the listed ingredients. I formed the opinion that the warning about not mixing was mostly about some /other/ kind of coolent from the past. Also, it seemed to me that the main difference between Orange and Green additives was different regulations in Japan/Eurupe/USA, that made USA components illegal in Europe/Japan. The secondary difference then was that, having tested and specified a coolent mix, Japanese/European car companies with long warrenties were disinclined to say “Oh, and anything else you put in will probably be OK anyway” In the end, I decided that it /probably/ wouldn’t make any difference which I put in /my/ engine, but even then that nobody had tested or guaranteed anything other than the manufacturers specification. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [May 5, 2017, 7:44am UTC](https://boards.straightdope.com/t/car-engine-coolant-types/785874/6 "2017-05-05T07:44:48Z")
don’t use the green stuff in any modern car. pretty much every car maker still uses ethylene glycol with a hybrid organic acid (HOAT) anti-corrosion package. if you put green stuff in your car, you trash that and at best you’ll need to change it within a couple of years. ---
**Author:** ![Flyer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/flyer/32/7298_2.png) [@Flyer](https://boards.straightdope.com/u/Flyer)\ **Post date:** [May 5, 2017, 4:42pm UTC](https://boards.straightdope.com/t/car-engine-coolant-types/785874/7 "2017-05-05T16:42:39Z")
From various sources that claim to be automotive experts: > [@](#): > > Prestone(R) Extended Life Antifreeze/Coolant is compatible with ANY antifreeze/ coolant - regardless of color - for use in ALL makes and models of cars and light duty trucks. [http://www.oreillyauto.com/site/c/detail/AFZ2/AF2000/N0496.oap?ck=Search\_N0496\_5235192\_-1&pt=N0496&ppt=C0059](http://www.oreillyauto.com/site/c/detail/AFZ2/AF2000/N0496.oap?ck=Search_N0496_5235192_-1&pt=N0496&ppt=C0059) > [@](#): > > RAY: The experts we spoke to at SAE (the Society of Automotive Engineers) said that you can mix up to about 15 percent traditional coolant in your OAT coolant before you have any real effect on the corrosion inhibitors. So if, for example, you just top up your OAT coolant with a few cups of traditional stuff, nothing’s going to happen. But if you go beyond that 15 percent threshold, then it makes sense to EVENTUALLY drain out the coolant and fill it up with all one or all the other. > > TOM: It’s certainly not an emergency. As we said, nothing is going to break, burn up or melt. And even if the rust-inhibition properties were compromised, you could still go a year or even several years without any negative effects. But it would be prudent, during your next service, to drain out a mixed batch of coolant and go with one type or the other. [http://www.cartalk.com/content/i-have-question-about-antifreeze-many-months-ago-my](http://www.cartalk.com/content/i-have-question-about-antifreeze-many-months-ago-my) > [@](#): > > Both conventional green and Dex-cool coolant are mostly the same thing: ethylene glycol (one of the alcohols). The difference is in the anti-corrosion additive package. Green coolant uses metal salts to provide a coating over any exposed metals in the cooling system. Dex-cool uses a different technology, one based on organic acids to reduce corrosion. Organic acid-based coolant can have a service life of five years in vehicles designed to use it. Green coolant should be flushed and changed every two years. > > Mixing the two means the Dex-cool should be changed within two years. > **[How quickly do Green (Ethelyne Glycol) and Orange (Dex-Cool) Coolants react?](https://www.quora.com/How-quickly-do-Green-Ethelyne-Glycol-and-Orange-Dex-Cool-Coolants-react)** > > Answer (1 of 5): Not to worry. They won’t turn into goo that plugs up the engine’s cooling system. > > Both conventional green and Dex-cool coolant are mostly the same thing: ethylene glycol (one of the alcohols). The difference is in the anti-corrosion... > [@](#): > > Hybrid Organic Acid Technology or HOAT: This coolant is usually dyed yellow but comes in other colors like green, pink, blue, red and orange, which leads to a lot of confusion. [https://www.hemmings.com/blog/2014/08/01/tech-101-the-colors-of-antifreeze/](https://www.hemmings.com/blog/2014/08/01/tech-101-the-colors-of-antifreeze/) > [@](#): > > According to industry experts, if you do not know what coolant is in the vehicle and you top off with another brand, nothing bad is going to happen. [http://blog.chiltondiy.com/2013/06/which-antifreeze-is-right-for-your-vehicle/](http://blog.chiltondiy.com/2013/06/which-antifreeze-is-right-for-your-vehicle/) ---
**Author:** ![rbroome](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@rbroome](https://boards.straightdope.com/u/rbroome)\ **Post date:** [May 5, 2017, 10:24pm UTC](https://boards.straightdope.com/t/car-engine-coolant-types/785874/8 "2017-05-05T22:24:19Z")
> [@Flyer](#): > > If you check the owner’s manual of every car made in the last 20 years or so, it screams to high heaven that there is ONLY ONE!!! proper kind of coolant to use. This is accompanied by almost-Lovecraftian warnings of doom and severe damage if you use any other type of coolant. > > On the other hand, go to Walmart or any auto-parts store, and every major manufacturer of coolant (including the private labels, such as Walmart’s brand) claim that their product will work in any engine, with any type or color of coolant. This claim is consistent across all price levels. > > So which is correct, or at least closer to being correct? As I understand it-it depends. There are certain cars, at least certain model years of cars, that can be damaged by the wrong fluid. A few minutes googling will provide you with more than you want to know. The problem as I understand it is that for the vast bulk of cars sold in the US (as I remember the story, this problem started with one or more German automaker and has spread to others) there won’t be a problem. Your challenge is to determine whether your car is one of the exceptions. And the best place to determine that is the car manual. Which as you pointed out, has large screaming warnings that if you used any fluid except the exact fluid from that manufacturer, they can’t be responsible for the consequences. Are you feeling lucky? Personally, I recommend doing the research. I did-now I have 2 containers of coolant in my garage that I will never be able to use… Sigh. I wasn’t lucky. One good rule-don’t mix the coolants. Whatever you decide to use, use only one kind. And Flyer did the research. I was mostly correct…, I still wouldn’t mix coolants. Seems like an unnecessary risk ---
**Author:** ![anomalous1](https://avatars.discourse-cdn.com/v4/letter/a/e56c9b/32.png) [@anomalous1](https://boards.straightdope.com/u/anomalous1)\ **Post date:** [May 5, 2017, 10:35pm UTC](https://boards.straightdope.com/t/car-engine-coolant-types/785874/9 "2017-05-05T22:35:43Z")
I only use the green monster stuff. Too many issues can be caused by that Dex-Cool garbage. Never had a problem. ---
**Author:** ![Weisshund](https://avatars.discourse-cdn.com/v4/letter/w/ba8739/32.png) [@Weisshund](https://boards.straightdope.com/u/Weisshund)\ **Post date:** [May 7, 2017, 7:42pm UTC](https://boards.straightdope.com/t/car-engine-coolant-types/785874/10 "2017-05-07T19:42:44Z")
> [@anomalous1](#): > > I only use the green monster stuff. Too many issues can be caused by that Dex-Cool garbage. Never had a problem. Unless you are putting it into a system with copper radiator or heater core, or any copper piping there should be no issue per say. The good old Green can go in anything, the downside is the corrosion inhibitor wears out, which it always did. The orange can only go in systems that have no copper, it’s upside is the corrosion inhibitor lasts a lot longer. The antifreeze part of the good old green stuff never wears out, and you can actually but the lube/anti corrosion to add back to it, but knowing what kind of crap builds up in the cooling system over time, i am still up for a flush and refill every so often. Even if you want to recycle and rejuvenate good old green, nice to get the junk out of the cooling system. ---
**Author:** ![anomalous1](https://avatars.discourse-cdn.com/v4/letter/a/e56c9b/32.png) [@anomalous1](https://boards.straightdope.com/u/anomalous1)\ **Post date:** [May 8, 2017, 12:11am UTC](https://boards.straightdope.com/t/car-engine-coolant-types/785874/11 "2017-05-08T00:11:22Z")
> [@Weisshund](#): > > Even if you want to recycle and rejuvenate good old green, nice to get the junk out of the cooling system. This. I suppose is the most important about it, doesn’t really matter what type of radiator or cooling system, but a flush every now and then definitely needs to be done to keep things working. I check my fluids once a week and whenever I check the reservoir it’s still bright hulk green, no rusty brown color, flakes or anything. I had the radiator changed out a while back with an aftermarket, really cheap considering my car and I am making sure to take good care of it, never want to go through that again. You know, the driving in the summer with the heat on and hood cracked (on city streets, don’t try that on a highway)