Which Antifreeze is Right for Your Vehicle?

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Story and Photography by Jim Marotta

Back in the day, no matter which brand you chose, antifreeze was green. The glycol-based formula contained silicates as corrosion inhibitors. You mixed the antifreeze 50/50 with water and poured it in the radiator. As the engine operated, the antifreeze performed its primary duties of carrying heat to the radiator, preventing freezing (hence the name) and protecting against corrosion in the cooling system. You simply changed the antifreeze at the prescribed service interval.
Today, with different types of antifreeze technology in a rainbow of colors, confusion abounds among automotive people and consumers alike as to what color antifreeze is best. The easy part is that most antifreeze manufacturers still make coolant with ethylene glycol (EG), a type of alcohol made from ethane. Manufacturers also make more environmentally friendly versions with less-toxic propylene glycol (PG), a similar compound made from propane.
Evolving Antifreeze
Inorganic Acid Technology (IAT) is the chemical basis for the traditional green antifreeze. IAT contains either EG or PG and is usually fortified with silicate or phosphate additives to make it compatible with metal cooling system components. The generally recommended replacement interval is every three years or 36,000 miles. The owner’s manual or maintenance chart from ChiltonPRO.com and ChiltonDIY.com shows what the vehicle manufacturer recommends for each specific vehicle.

IAT and OAT are two types of antifreeze technology

Inorganic acid technology is the chemical composition for the traditional green or yellow antifreeze (right). Organic acid technology is the orange coolant on the left.

Organic Acid Technology (OAT) is a Long Life Coolant (LLC) / Extended Life Coolant (ELC) widely used in Europe before its introduction in North America. OAT is usually EG. The generally recommended replacement interval is five years or 150,000 miles; find out what the vehicle manufacturer’s recommendations are for your car or truck.

Organic Acid Technology (OAT) is a Long Life Coolant (LLC) / Extended Life Coolant (ELC)

An example of an organic acid technology long life/extended life coolant

Hybrid Organic Acid Technology (HOAT) combines IAT and OAT with nitrites. Antifreeze manufacturers often refer to it as “global,” indicating on the bottle that it meets or exceeds the specification “G-05” for most vehicles newer than 2002 and “G-11” or “G-12” for Volkswagen and Audi. The generally recommended replacement interval is five years or 150,000 miles, always check your vehicle manufacturer’s recommendations for your car or truck.
Why All the Different Coolant Formulations?
In the early 1980’s Ford was working with antifreeze manufacturers to come up with a formulation to meet global needs. European countries had very hard water and since water is 50% of the antifreeze mix, water quality dramatically affects the overall mix. As European manufacturers were abandoning phosphate-based technology because phosphates tend to form scale, Japanese manufacturers were moving away from silicates, which tend to destroy water pump seals.
The first alternate coolants were hybrids combining carboxyl and silicate technologies. Ford started using them after extensive durability testing (more than 40 million fleet test miles on every vehicle platform that Ford had) in the early 1980s. At about the same time, Mercedes and VW were also using hybrid formulations.
In addition to better corrosion inhibitors for the global market, other issues precipitated formula change. Toxicity and environmental concerns are behind the use of PG rather than EG, while the promise of longer-lasting engine protection and less maintenance spur development of the newest formulations, such as Nissan’s blue coolant, which is designed to last ten years or 135,000 miles.
Does Antifreeze Break Down?
Engine antifreeze does break down, forming corrosive organic degradation products. Antifreeze buffering agents inhibit this corrosion. Since most antifreeze leaks out of the vehicle, most systems are “topped off” with fresh antifreeze, extending its life somewhat. How much depends on the type of antifreeze added.
Can You Mix Antifreeze Technologies?
The one universal coolant that all agree on is water. For best performance, water needs a little help. What happens when antifreezes are mixed? A lot of the confusion about mixing coolants stems from early work with carboxyl coolants. In an American Society of Testing and Materials (ASTM) test, mixing IAT and OAT coolants resulted in more corrosion than either antifreeze alone. Subsequent tests revealed a testing error: the corrosive environment occurred because the coolant was too dilute.
It is best to use the same type of coolant originally used in your car or truck, or the vehicle manufacturer’s recommendations. 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. Only when dilution rates border 50% is the effectiveness of each coolant’s inhibitor package compromised. However, when mixing coolants, the recommended coolant change interval will degrade to that of the shorter-life coolant.
Proper Maintenance is Key
As with anything automotive, proper maintenance is the key to longevity. More important than the type of antifreeze you use is to maintain the cooling system properly by maintaining freeze point protection and proper coolant level. Almost all coolants work best at the ideal freeze point mixture, which for most parts of the country means a 50/50 antifreeze-to-water mixture. At this level, antifreeze protects to -34°F and boil-over protection to 257°F. In addition, maintaining proper freeze point protection ensures corrosion inhibitors are present at intended levels.

A handy tool provides coolant concentrations

Maintaining the cooling system properly by maintaining freeze point protection and proper coolant level is critical. Here a handy tool provides coolant concentrations.

Vehicle manufacturers design cooling systems to operate full of antifreeze. A system that is constantly low on coolant can create an extremely corrosive environment due to the aggressive nature of the vapors of a glycol/water mix. These steam vapors are more corrosive than either fluid by itself. To check your coolant system capacity, simply refer to your vehicle’s capacities chart at ChiltonDIY.com, ChiltonPRO.com, or your owner’s manual.
If you choose to maintain your cooling system yourself, keep in mind that all types of antifreeze are poisonous. Animals and humans can be attracted by its sweet taste. Always recycle antifreeze properly.
Distilled Water is Best
In almost every part of the country, tap water contains minerals such as magnesium and calcium that can form deposits in a cooling system, especially on the engine’s hottest parts. The water you use to mix the antifreeze is critical. Premixed coolants are mixed at the factory with distilled water. Use distilled water, not tap or filtered water, when you refill any cooling system.

Use distilled water and coolant to maintain the cooling system

A system that is constantly low on coolant can create an extremely corrosive engine environment

Coolant Keeps Working After the Engine Quits
Having the proper coolant level is still important after shutting off the engine. As the coolant stops flowing and the engine temperature increases dramatically, areas of localized boiling can send large shock waves through the engine wreaking havoc on components, especially those made of aluminum.
A subscription to ChiltonDIY or ChiltonPRO, with comprehensive maintenance charts and fluid capacity specifications, will give you all the information you need to keep your cooling system in top shape this summer.
James Marotta A muscle car enthusiast and drag racer, Jim Marotta is a freelance automotive writer with more than 20 years experience in the automotive industry.

63 responses to “Which Antifreeze is Right for Your Vehicle?”

  1. Bill says:

    I have heard that mixing yellow with green causes a jelling affect
    Is miss and blue comparable with all others ??

    • ChiltonDIY says:

      HI Bill.
      It is best to use the same type of coolant originally used in your car or truck. To be sure follow the vehicle manufacturer recommendations. You can find them in your owner’s manual and in ChiltonDIY when you subscribe for your vehicle.

  2. Dan says:

    Great article, it is always a good idea to use distilled water instead of tap water! Tap water will leave deposits in the engine.


    hv a 89 98 olds regency.

    problem need to know how to replace the engine freezout plugs. The plugs are very hard to get at and working on my back don’t help either. The 2 plugs on the drivers side but need to know what kind of tool needed to remove them.

    If you can help it would be greatly appreciated. been working on my vehicle for 20 yrs,

    tu mike

    • ChiltonDIY says:

      Hi Michael.
      Drill a small hole in the middle of the freeze plug, and then thread a long sheet metal screw into the hole and use a slide hammer to remove the freeze plug. The freeze plug can also be removed using a hammer and a punch. Be careful not to push the plug inside. Cock the freeze plug and pull it out using pliers.

  4. Greg Jantti says:

    Good article as always. Real good information to have with the weather we have had lately. Keep up the good work.

  5. charles emory says:

    Good one.Once green fluid comes out from my antifreeze tank and pour out everywhere. Next day I take my car to Apex specialized automotive in Edmonton and after checking my car they said like you don’t want to worry the raw antifreeze chemicals as they come from Dupont by the tankcar load are clear to light tan in color. Each company differs in their colour to give some unique look.

  6. Lola says:

    My husband has a 2006 Dodge Dakota. He needs to know what kind of antifreeze he can buy that will mix with the antifreeze he has in his truck now?
    Thanks for your help.

    • ChiltonDIY says:

      Hi Lola.
      Check your ChiltonDIY subscription for your 2006 Dodge Dakota or the owner’s manual to see what type of antifreeze is suitable for your husband’s truck. If he doesn’t have the owner’s manual, the 2006 Dakota manual is available free from the Dodge website at: http://www.dodge.com/en/owners/manuals/.
      In addition, many times there is a sticker on the radiator that explains what kind is best.
      On the back of the antifreeze bottle there is a list the vehicles that the brand applies to. However, there isn’t much need to worry, as most major brands of antifreeze are compatible with any other antifreeze (and color) and for all cars and trucks. Just read the label first to make sure.

  7. Ralph says:

    I understand the need for Antifreeze in colder states, but here in Phoenix, sometimes the coldest time of Winter is around 40-50. Well above the freezing poin, but is there another benefit to using antifreeze over water rather than making sure your engine doesn’t freeze up?

    I’d love to hear your response, thanks!

    • ChiltonDIY says:

      Hi Ralph, great question!
      Older cars (and we’re talking 1920s and 30s) got along with just using water in the radiator, because sometimes there were no other options. However, it is like saying drinking plain water will provide a body the bare minimum of what it needs. Why not drink water with minerals and vitamins in it? Same for your car. With the use of a wide range of materials in building engines these days, they need so much more protection than their predecessors did.
      The largest benefit of antifreeze is corrosion prevention. When you have water and iron together with oxygen, rust is a result. Antifreeze provides a protection against rust, something you certainly don’t want inside your engine. As well, antifreeze transfers heat much better and quicker than water alone. It prevents scale buildup (from the chemicals and minerals found in hard water).
      Better suited for your hot climate than plain water, antifreeze is much more stable at high temperatures — meaning it won’t boil or turn to steam as easily as water alone because it raises the boiling point of the mixture.

  8. Nissan 300ZX says:

    Hey there,

    My 300zx is from the 80s. I keep noticing a buildup of gunk in my overflow bottle.

    Any idea if a specific antifreeze will stop this?

    • ChiltonDIY says:

      Hey there.
      Have you ever used a stop-leak product? It’s my personal experience that stop-leak products can cause a gunk build-up in the bottle. If not, you should pull the bottle and clean it out. As to any specific antifreeze stopping it, I can’t say. Personally, if there’s a lot of gunk, I’d drain and flush the system and then refill it with a good quality, name-brand antifreeze in 50-50 antifreeze/water solution.

  9. Bruce says:

    Want to find out about which Antifreeze is good for a 2005 Ford F250 Super Duty Diesel
    Some have said not to use the extended life and the Manufacture mentions Liquid Gold with a stabilizer. Can you shed some light on this as I’m very confused as to what is best to use

    • ChiltonDIY says:

      Hello Bruce.
      There is a science behind the new engine coolants, with the advent of lighter more efficient engines. Heavy-duty diesel OEM (original equipment manufacturer, eg, Ford) recommendations have a wide array of possibilities. In the industrial sector, some OEMs require the use of silicated coolant, while others require silicate-free for heat transfer concerns. And yes, they have testing procedures and special tools. If you’re not sure about the condition and quality of your coolant just change the fluid. Be sure to follow the manufacturer’s recommendations! Vehicle manufacturers are now more than ever using science to get the most out of your vehicle’s cooling system and to optimize your vehicle’s performance.
      We recommend you follow Ford’s specifications to properly maintain your high-technology cooling system.
      Beyond adding the specified coolant, test the level of nitrates periodically as indicated in Ford’s maintenance schedule for your 2005 Ford F250 Super Duty Diesel. Here is an excerpt from Ford’s Power Stroke® Diesel Operating, Maintenance & Care Tips:
      “Engine coolant system nitrite strength should be checked and serviced at the mileage or equivalent hour intervals specified by the maintenance schedule. Check coolant nitrite strength using the 3-Way Antifreeze Test Strip kit Rotunda # 328-00001 to determine if additive is required. If the nitrite strength is between 800 ppm & 300 ppm add 32 fl. oz. (946 mL) of Supplemental Coolant Additive Motorcraft VC-8 or equivalent. If nitrite strength is below 300 ppm flush & refill engine coolant (refer to Motorcraft Premium Gold Engine Coolant Change Record) – Do not add Supplemental Coolant Additive if flush and refill is required.”
      You’ll find Ford’s diesel maintenance tips, owner’s manuals and more for your 2005 Ford F250 Super Duty Diesel at: https://owner.ford.com/servlet/ContentServer?pagename=Owner/Page/OwnerGuidePageVehicleLookup&BackToLogin=Owner/Page/OwnerGuidePage&ord=9276196
      Stay abreast of changes at the Ford owner’s site and with your ChiltonDIY subscription for easy-search technical service bulletins (TSBs; where Ford informs its dealers of changes and issues) and Recalls.

  10. Shawn Knockaert says:

    what brand of antifreeze do i use in a 2002 jaguar 3.0 litre x type

  11. Rasid says:

    Hi chiton
    I have 2012 Toyota camry xle and I need antifreeze and its blue what should I use …? Is peak 50/50is good ?

    • ChiltonDIY says:

      Hi Rasid,
      Use what Toyota recommends for your Camry. The fluid specification is in your owner’s manual as well as in your ChiltonDIY subscription. If Toyota makes changes in its specification, the change is often released in a technical service bulletin. You can check the bulletins and recalls for your Camry in your ChiltonDIY subscription.
      Peak 50/50 is a prediluted antifreeze and coolant, which means that there’s no need to add water. The benefit is that the water they use to dilute it is treated to remove some of the more corrosive elements. It is advertised to be good for all cars and trucks.

  12. samantha says:

    I have an Oldsmobile alero 1999 3.4 engine. What kind of antifreeze should I use?

    • ChiltonDIY says:

      Hi Samantha.

      Here is an excerpt from General Motors’ service manual for your 1999 Alero describing the type of coolant designed to be used in your Alero and why. Quality aftermarket antifreezes also acceptable if labeled for your 1999 Alero:

      This vehicle was manufactured with GM Goodwrench DEX-COOL™. GM Goodwrench DEX-COOL™ was developed to last for 240 000 km (150,000 mi) or 5 years, whichever occurs first. Make sure only GM Goodwrench DEX-COOL™ (orange-colored, silicate-free) is used when coolant is added or changed. Follow the instructions in Draining/Filling Cooling System.

      Notice: Pure coolant can be added to raise the boiling point of the coolant, but too much will affect the freezing point. Do not use a solution stronger than 70 percent, as the freeze level rises rapidly after this point. Pure coolant will freeze at −22°C (−8°F).

      A 50/50 mixture of ethylene glycol (GM Goodwrench DEX-COOL™) and water will provide the following protection:

      •Give freezing protection down to −37°C (−34°F).
      •Give boiling protection up to 129°C (260°F).
      •Allow the sensors and switches to operate as designed.
      •Protect against rust and corrosion.
      •Help keep the proper engine temperature.
      •Let the warning lights and gauges work correctly.

      Recycled coolant is also an option, according to a technical service bulletin (TSB) that General Motors issued to its dealers, you can check the full text in your Chilton subscription.

      General Motors supports the use of recycled engine coolant for warranty repairs/service, providing a GM approved engine coolant recycling system is used.

      Lastly, Samantha, antifreeze is poisonous to humans and animals. It is also toxic to the environment so be sure to recycle. Earth911.com is a good resource.

  13. Rick says:

    Will the standard tester shown in this article check the freeze point of all the a/f options including the new blue coolant accurately? Or do you have to utilize a refractor?

    • ChiltonDIY says:

      Great question Rick! Most antifreeze tester measure the specific gravity of ethylene glycol/water mixes. For OAT and HOAT antifreezes, a refractor-type tester is needed.

  14. Sandra Jackson says:

    I have a 2000 ford focus what type of antifreeze does my car need.

    • ChiltonDIY says:

      Thanks for reaching out Sandra :-)
      Ford originally specified Ford Premium Engine Coolant E2F2-19549-AA, Specification: ESE-M97B44-B for your 2000 Focus.
      While Ford is the maker of your “original equipment” Focus, other companies make components and fluids for it as well, these companies are part of the “automotive aftermarket.” You will see these products in automotive parts stores.
      In addition to the Ford Premium Coolant, you can also use a quality aftermarket antifreeze that is labeled for use in the 2000 Ford Focus. In some cases, recycled coolant may be available, it has the advantages of being less expensive while saving resources.
      Antifreeze is *toxic* to humans and animals, as well as the environment. It can have a sweet taste, so pets and children may be attracted to it. Always leave unused antifreeze in its original marked container, out of reach of children. Never leave antifreeze out, such as in a drain pan, where it can be consumed accidentally.
      Antifreeze is a serious safety concern for both cats and dogs,” says Mindy Bough, Vice President of Operations for the ASPCA Animal Poison Control Center. “Unfortunately, just a few licks can cause kidney failure and death in a matter of days—even a small amount that may be licked off a paw is enough to cause serious harm.
      The Environmental Protection Agency says: “Waste antifreeze should never be disposed of down storm drains or into surface waters because it causes serious water quality problems and may harm people, pets or wildlife. Doing so is illegal and punishable by fines of up to $25,000.
      Return waste antifreeze to the store where you purchased it, or check out earth911.com for resources.

  15. Drew says:

    Question for you experts at Chilton: I have just replaced the Radiator, Water pump all hoses and have chemically flushed the system and recovery tank thoroughly b4 this work and afterwards with plain distilled water in my 2003 Jeep Grand Cherokee with the bulletproof 4.0l 6 cylinder engine. I understand the Mfg. recommends Hoat antifreeze however I would like to run the “Universal Global Type Prestone” EG as the yellowish green color is easier for me to judge the degradation and accumulated filth over time then the Mopar Hoat orange version. I am wondering since I have flushed out the system thoroughly of the “Organic Acid Type” Antifreeze will it be ok to run this EG (Ethylene Glycol) based antifreeze instead of Hoat. Simply put its easier IMO to visually judge the dirt buildup in this Yellow EG based fluid then the Orange Hoat. My thought would be if their was any further visually observed reaction between the leftover Hoat deposits/corrosion with the new EG I would just drain and replace with new EG in a month or two. This question also pertains to my Dexcooled 2000 Silverado and 1999 GTP which I want to change to EG as well. I will hold Chilton’s harmless for your answer as I know the tendency is to stick with the OEM coolant. But what’s the real skinny on this? Aren’t all cooling systems basically made of the same types of steel, aluminum, plastic and rubber regardless of the manufacturer? I know if anyone knows, it will be you guys… And this has been the subject of debate amongst my little group of self professed know it all mechanics since forever.

    Thank You as I really hate HOAT!

    • ChiltonDIY says:

      Hi Drew.

      The two antifreezes are not compatible. I prefer HOAT because of its superior protection.

      Here’s the explanation from Chrysler’s service information for the 2003 Grand Cherokee:

      CAUTION: Use of Propylene-Glycol based coolants is not recommended, as they provide less freeze protection and less corrosion protection.
      The cooling system is designed around the coolant. The coolant must accept heat from engine metal, in the cylinder head area near the exhaust valves and engine block. Then coolant carries the heat to the radiator where the tube/fin radiator can transfer the heat to the air.
      The use of aluminum cylinder blocks, cylinder heads, and water pumps requires special corrosion protection. Mopar® Antifreeze/Coolant, 5 Year/100,000 Mile Formula (MS-9769), or the equivalent ethylene-glycol base coolant with organic corrosion inhibitors (called HOAT, for Hybrid Organic Additive Technology) is recommended. This coolant offers the best engine cooling without corrosion when mixed with 50% ethylene-glycol and 50% distilled water to obtain a freeze point of -37°C (-35°F). If it loses color or becomes contaminated, drain, flush, and replace with fresh properly mixed coolant solution.
      CAUTION: Mopar® Antifreeze/Coolant, 5 Year/100,000 Mile Formula (MS-9769) may not be mixed with any other type of antifreeze. Mixing of coolants other than specified (non-HOAT or other HOAT), may result in engine damage that may not be covered under the new vehicle warranty, and decreased corrosion protection.

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