The Dangers of Mixing Green and Orange Coolant (2024)

1. I went to monro for a simple oil change and now my car has all these symptoms

   What exactly happens when these coolants are mixed?
   The coolants chemically react and form a gel rather than a liquid. The coolant stops flowing through the system, clogs up coolant passageways and water jackets, radiators, and heater cores. The water pump overheats and fails due to a lack of lubricant in the coolant. Head gaskets blow, heads warp, and the engine suffers major damage.

2. It’s complete nonsense….you can mix them….gm and ford just want you to buy the Orange more expensive…I mixed them 13 years ago….my car has 215000 miles have had zero problems…..it’s a total lie that you can’t mix them…

3. Eddie michniewicz..you dir are a complete fn idiot…u absolutely have no known knowledge of mixing nothing but maybe a drink…if u listen to this dumb ass u will most definitely overheat and blow a motor threw the hood…lmao..what a idiot

4. You can mix the two. Even the SAE says you can mix the two. Valvoline, Prestone, Peak, Autozone, NAPA, and O’Reillys all have green coolant labeled “works with any make and model” and “mixes with any coolant”. The antifreeze does not jelly. Mixing them can lead to reduced effectiveness of corrosion inhibiting additives and thats all. Antifreeze is solely intended for keeping the water from freezing in winter when your car sits and the additives are there to keep your aluminum parts from corroding.

5. we mixed the two and got a slimmy sludge type of mixture. not good. had to do a radiator, water pump flush and new coolant put in

6. I would rather be safe than sorry. I bought a camaro SS AND it had a slimey mess in radiator so i flushed the hell out of it.

7. When you state it is bad to mix them, do you mean mix as in “I have a container of orange, and a container of green, and I mix them together and put them in the vehicle?” Or “The vehicle has orange in it, but I bought more and it was green, and I added it in.”

   See Also

   What Is The Difference Between Green & Orange Coolant? [Guide]The Difference Between Green and Orange AntifreezeAdvance Auto Parts - Down for MaintenanceChoosing the Right Coolant for Your Car

   Reason I ask, I have a Jeep GC Leredo (horrible car, I would only recommend to those big trucks that crush cars) and the water pump was going bad, and the coolant was leaking, and I had to wait about a two weeks to have it repaired. Since it became to leak daily, sometimes twice a day, I began putting water in it, because I couldn’t afford to continue adding coolant and it leak out. Prior to this issue it had orange coolant in it, but again I began putting water in it for about two weeks that leaked right out. Now I have had a new water pump put in, and I went to the store to purchase coolant, and the gut said the colors didn’t make a difference, but told me the one I was purchasing was orange. I got home, my FIL who informed to get orange stated it was green and I did not need to put green in it. I figured it had been flushed basically from the water I put in it. Any insight?

8. Ive seen what happens to mixing green and orange antifreeze. It makes solids(gel or whatever, pretty gross stuff) inside the reservoir. DONT DO IT. Just by the concentrate for a dollar more than the 50/50 premixed, then add a whole jug of water with the concentrate, and you will have 2 gallons for only a dollar more.

9. I just bought a 1999 mercury cougar that overheats. I burped it and finally have heat but its still overheating. I have the green stuff in it and my manual says dex cool antifreeze only which is orange. Now i have to flush my system to correct the overheating problem.

10. I just spent $700.00 replacing the water pump on my 2012 Rage Rover Sport, because a gas jockey at my local full-serve station put green Prestone coolant instead of Orange. I guess that i should be happy that they don’t make Cyanide gas when combined and flood the car with poisonous gas , killing all it’s occupants. What a total rip-off ! What’s next – putting additives in your gasoline that make your engine explode if you don’t use gasoline from only one type of gas station ?!
    How can this be legal, are there not consumer watch-dog organizations to prevent this ?
    Hey Dan McTeague, you need to warn people about this as well as where and when the gas deals can be found .

11. first of all green and orange makes BROWN……… WHEN U LOOK AT YOUR OVERFLOW , DO YOU WANT TO SEE SOME SICK BROWN COLOR FOR SO CALLED COOLANT? WHATS WRONG WITH clown that would do this anyway

12. Use the right stuff that is recommended by the manufacturer and stfu.

13. I once mixed dexcool with standard green antifreeze. The car immediately heated up, fogged up the windshield and not even a month later, then headgasket was blown. Do NOT mix your antifreeze when it’s specific. Dexcool is crap and should not be used, but you must FIRST completely flush your system before you make the change to standard antifreeze. I repeat, do NOT mix your antifreeze’s. If in doubt, flush it out!!!! If you’re running Dexcool, consider making the change. It’s total garbage that sludges up your engine.

14. Killed my motor in my expedition when I mixed the two cost me a new engine 2800 dollars…Yeah mix at your own risk………😠

15. I came here specifically to check on this issue before adding to my neighbor’s coolant reservoir.

    Long story, but her life’s gone to sh*t, she’s had cancer three times, and she’s being told that the accident she was involved in — stationary, had an 80-year-old retard back out of a parking space, pause, then rip two car lengths backwards into her front end because he didn’t realize that he was still in reverse — is 85% her fault. Nice arbitrary figure. Let’s forget that she wasn’t even moving.

    There was no radiator issue prior to this, but now there’s a leak after it sustained a significant impact, and the rival insurance company’s adjuster insists that the damage wasn’t at all related to this debacle. Evil morons.

    Anyway, I work on my own car, which is an older Honda Civic. I came here because I thought there was a compatibility concern between the two formulations, and I have a jug o’ green while I got a well-lighted look a little while ago to see orange in her reservoir. I’m going to get some of the orange, especially after reading the overwhelming number of similar horror stories here. Her car is a newer Civic, and Hondas are supposed to have Honda Genuine Blue, So. No time to do it ‘right’, but I’m not gonna be yet another problem in her life. ; ]

    It’s also worth mentioning that anyone can leave a comment in a section like this, so there’s no way of determining intent or sincerity — or the full scope of someome’s stupidity. I have no idea if someone truly mixed these two types 13 years ago and is driving problem-free today with 215,000 on the odometer. Might be a 100% bullsh*t tale to stir things up. There are people who do crap like that for fun.

16. Have an 04 Pontiac Grand Prix bought brand new and it had the orange stuff in it. Within 8,000 miles that car overheated and the dealership had to flush and fill all fluids. Said they had never seen antifreeze coagulate like that. They claimed the thermostat was stuck open so that was covered under GMs warranty, then charged me $700.00 for the remainder! Notice on those orange jugs how they now say it don’t coagulate! Thermostats that are stuck open don’t cause an engine to overheat! I loved that car because I built the engine cradle and it,s still in the drive but that was the LAST GM product I ever bought!

17. Okay I’ve had a heating problem with my Chevy Silverado 1994 I bought antifreeze it was Green I put it in then threw out working on it I bought some more and it was Dexcool General Motors it overflowed spit out so I bought more down here at the store and it was green I put it in there how do I fix this problem please let me know ASAP you know a man needs his truck laugh out loud

18. I put in green coolant and without looking put in like half a litre of red coolant with it be ok or do I have to drain it again?

19. I have a 2004 Chevy Impala LS. Unfortunately, allowing a friend to use my car and “service” it for me was extremely costly. They noticed the car coolant was low and put the older, standard GREEN in. Unknowingly I kept driving the car until the engine overheated and cost three thermostats, 2 radiators and an engine. The car has been flushed over 10 times in the course of the last year and the DEXCOOL that is supposed to be in it still turns almost BROWN within a 10 mile drive. Heat is diminished and the car does idle much hotter than it should. Does not overheat at the moment but does go just over the halfway mark. I would HIGHLY recommend NEVER mixing these two as the cars are specifically designed for this and with today’s technology and sensors repairs are much MUCH expensive. Hope this helps folks consider their options.

20. Please, please, please…If you are reading these comments…please, just put the proper coolant in your vehicle. Be it an automobile or ATV or Side by Side. I am a technician & I have to deal with this problem quite often. The end result is an expense that could have been avoided. Check your systems regularly & keep them maintained!!!

21. I called Cummins and talked to a tech. I’m taking green coolant out of a 19 year old diesel engine. Don’t know how long that coolant has been in there. I bought the stuff everyone is hot about Zerex. It’s yellow, or orange if you like. Looks yellow to me.
    Cummins says if you rinse the old green coolant out well the residue left over won’t react badly with the new yellow coolant.
    Then a neighbor says, “If there’s green in there and it’s worked well for 19 years (hopefully been changed many times in 19 years) stick with green.
    Cummins says if you mix 50/50 green and orange you might have trouble. But as long as you flush or rinse well with distilled water a few times (I’ve done three rinses and I’m going for one more) then the old stuff is pretty well gone and you can add what you like.

22. So my car was overheating, went to dg and got coolant poured about 3 cups into my orange coolant, will my car be okay?????😶😶

23. I just went to fill my girlfriends car with fluids today before a long trip. Well, I noticed her coolant was low so I filled it. It said special coolant only on the cap… But i thought it was more of a “antifreeze only, no water” type of thing. Well, needless to say…the car now overheats and is non driveable. It’s a 2005 PT Cruiser and it’s her only car and I feel like the biggest piece of crap in the world. I didn’t drive it far… maybe 2 miles before it overheated. Anyone have suggestions on how to fix it?

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25. I just put dex cool in my 2006 buick, it had green in it but i followed mnftr instrucctions…now have overheating problems…smh

26. Color didn’t used to necessarily matter but it matters now! coolants through the years have come in many colors. -When all that was available was the old school glycol, it came in green and orange and long life coolant also could be a different color. No slime created by mixing those as they have the same chemical composition.
    New “OAT” coolants- i have seen purple, and apparently orange is common.
    Don’t pay attention to the color, pay attention to what type of coolant it is. Don’t mix the new technology Coolants with even a little bit of the old school stuff because it has a different chemical composition and sounds like it will turn the insides of your cooling system into a soggy diaper.

    See Also

    Prestone® Prime® DEX-COOL® Compatible Orange Antifreeze + Coolant - Prestone® Total Protection

27. What about Prestone? It says on the label (and on their website), “Works with any color antifreeze,” and “Thanks to its unique and patented formula, Prestone Coolant/Antifreeze remains the only coolant on the market that can be mixed with another product within the cooling system without causing damage.” So what’s the real story? Can Prestone be mixed with Dexcool or not?

28. I mixed added green f*cked up the sustem turned to clay pluged everything dam dont mix

29. This may explain why GM had a LOT of Chevy engines go bad around 20 year ago!! Problem ruining engines was with the cooling system! Never knew till checking on this today they changed to “new” anti freeze about that time!!!

    Had such bad experience with a VEGA I haven’t bought another Chevy since!!! That piece of crap was WORST car I ever bought!!! Vega looked good but…… MUCH, MUCH worse that the used Corvair I had.

30. i mixed green pee and orange poop in the toilet. what a mess!

31. Never heard of thus til today but I did learn the hard way that you cannot mic stop leak with any antifreeze period because it can plug your heater core

32. Did this thinking nothing of it, in kenworth T8, figured two could be mixed… Do not mix! Turns into thick black oil! Sitting here now waiting for mechanic to come in….

33. I wonder how much of a mixture is a problem? I absentmindedly poured a few glugs (probably less then 8 ounces) of green anti-freeze into a tank about an inch below the min line that had orange before my brain registered what I was doing. However, two days later and it seems to be working fine. The color of the anti-freeze in the tank is still orange, and the viscosity is still just slightly thicker then water.

    I am pretty close to the 60K mile mark, so I might just flush the system next time I take it in for maintenance just to be safe. And I plan to dispose of the old green anti-freeze anyways since it is a 20 year old bottle that was sitting in the garage when I bought my house (it even has an advertisem*nt to win tickets to Superbowl XXXVI).

34. Bought a 95 Tahoe 2 door 4×4 that someone had mixed the two coolants it sludged up the whole damn works cost an arm and a leg to get it fixed. Truck wouldn’t hardly run misfiring and stalling it sludged up all the sensors. Shop flushed it on their machine like 20 times. It runs great now luckily no damage was done. DO NOT MIX ORANGE AND GREEN COOLANT!!!!!

35. Forget all this fancy coolant put cheap Walmart or any generic green stuff in flush it once year don’t go past 2 years never have a problem. Only downside to the old stuff is after 2 years it breaks down into a strong acid. Even stuff sitting in a bottle on your shelf will breakdown.

36. I am an ASE certified mechanic. If you have mixed coolant. Please drain and flush your system. There are some flush additives sold that will help. If you have overheated you may have blown a head gasket. But before we go there flush your system. Next drain you system completely. Fill your system with the right coolant and make sure you purge all the air out. Let the car idle for about 30 minutes check if the fans have come on if it hasn’t overheated. Drive the car hopefully all is ok. If not we need to see why. There are kits to check if the head gasket is blown. You may have a clogged radiator. The problem most people have is a car is 5+ years old and no one has changed the coolant. The system needs to be serviced. Coolant does break down. When it does you engine and cooling system suffers.

37. I’m reading these comments in awe, so many of you need to stop driving period. There’s a reason you aren’t supposed to mix coolant types and only use the manufactured recommended fluids only as they are specifically designed for that vehicle for a reason. I will tell every single one of you arguing that you “Can” mix coolant types, please go take an automotive course and learn something… NO you do NOT mix any coolant type with another whatsoever.

38. Yes, it is true. No conspiracies here just read your manual. I added just a little of the green stuff to the radiator when I was in a rush and BAME that stuff really reacts to each other. It stopped up my radiator, plugged up my heater core, and corroded my thermostat and radiator cap. I thought the head gaskets were blown. It took quite a flushing to get all that crap out of my cooling system. When I opened my drain plug on the radiator it was completely stopped up, I had to flush threw that tiny hole with a special flushing tool to get it all out. Black sludge spewed out. DO NOT MIX.

39. 2007 Chevy Equinox…overheating at idle.
    Found out a family member topped me up with green while I was out of state.
    It really didn’t start overheating until after that…I thought it looked weird!
    Guess I have a flush (hopefully not more) to look forward to. ☹️

40. On my 2006 Silverado the over flu tank tell you DexCool is orange!

41. I mixed got goo and had to get a new reservoir and then flush the system.
    Pay the extra

42. Pingback: Does Coolant Have to Be 50/50? (Explained) - Automotive Nerd

43. It happened to me, turned into a gelatin type goo thankfully I caught it in time

44. never had a head head gasket leak in my 240z Datsun until I changed the green antifreeze with Toyota antifreeze there are 5 mall areas on the head that are leaking coolant also my thermos housing now has a small leak . I take good care of the z and have never let it over heat

45. Only a complete dumbass would do this, my father in law topped off my wife’s vehicle with the green stuff, ended up destroying the motor.

46. Glad I read this article and comments just in time. My friend selected an orange antifreeze to go into my 1992 Ford F-150 truck which currently has green anti-freeze in it. She was convinced that the label indicated “Universal for use with any color antifreeze” it would be safe. This antifreeze is YELLOW and contains
    Ethylene glycol, Diethylene glycol, water and “PROPRIETARY CORROSION INHIBITOR, PROPRIETARY INGREDIENT”. I will be going back to the store tomorrow…just in case!

47. My 2005 F150 5.4L spec says 27.1L converts to just over 7 gallons right? I drain my radiator and get 1/2 gallon. add back 2 gallons and am at the midline on the resevoir. Anyone want to enlighten me on the other 5 gallons that are supposed to fit in my system? I have added back Green antifreeze. I did not flush I have had no problems so far.
    thanks in Advance.

48. Well, I f*cked up guys. I’ll start off with, I drive a gmc sierra 2016, the ac went out so went to charge it, and noticed the antifreeze could be topped off. Not knowing sh*t about vehicles at this point in time, I grabbed the jug labeled for all vehicles.. and God damn, I’m chasing problems up sh*ts creek. Also mentioning, I let a friend tell me it’s okay to add water… well that’s what I did, and to an excessive amount.

    Fast forward to today, condenser is obviously leaking due to, most likely, the water boiling, creating pressure and blowing a God damn hole somewhere I can’t see. Moving on to the second problem, I’m losing power turning at stop lights or, more so, when the motor shifts into 3rd. My question here today is, I’m not seeing milky residue in the reservor, it does spill out white smoke through the exhaust, am I close by saying it could be a blown head gasket? Possibly allowing the antifreeze into the 3rd cylinder specifically, causing it to bog or lose power? I know there’s pressure tests to indicate fumes backing up into the coolant, but money’s tight. Anybody have any ideas?

    My emails Stratatouille257@gmail.com

49. I just wasted a good hour of my time reading all this crap. Some of it is f*cked up ridiculous. I just flushed mine and put in what I had lying around. 🤥

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