All Wheel Drive Auto: Independent Seattle Subaru Service


Which Coolant is Right For My Subaru?

Subaru Service Seattle

This comes up a lot it seems, we are often directed to a forum link or told that a Subaru dealer is stating something different than what is in the owner’s manual.

What I can tell you is that just like a software update after the software is produced as a result of something learned about behavior in the field Subaru will address things that come up that can negatively affect the ownership experience.  This is especially true when Subaru changed the oil change requirements to maintain warranty coverage on all Turbo models to 3750 miles instead of the Fantasy that is 7k interval oil changes that was printed in the owner’s manual.   Some Subaru Dealers are in fact suggesting cooling system services that differ from what Subaru printed in the manual I think they are correct in doing so.

I will do my best to try and explain which coolant is right for your Subaru at this time.

If you own a 1990 to 2002 2.2l or a 1995 to 1999 DOHC 2.5l you can use just about any type of regular Green Antifreeze/coolant.  You do not need to add any type of stop leak, I mean coolant conditioner, the service interval is every 30,000 or about every 2 years on average. This will hold true in most all Subaru Outbacks, Impreza, Forester, Legacy and WRX models.

If you own a 1999 to 2008 SOHC 2.5l you should use the O.E. Subaru Long Life Coolant that is green in color pictured below.  If you have not had the Head Gaskets replaced or they were done at the Dealer you should also use the Cooling system conditioner as well.  If you have had the Head gaskets replaced and the shop that made the repairs used the Six Star gaskets you can use normal green coolant and DO NOT need to put any stop leak I mean conditioner in the cooling system.

Starting in 2008 Subaru went to a new Super long life coolant, it was only supposed to be in the STI in 2008 and all other models by 2009 but we have observed plenty of 2008 Subaru Outback’s that came from the factory with Blue Super long life coolant rather than the green long life.    If what is in your car is green it needs to be changed every 30k, and if blue every 60k, if you want to try and go 100k you do so at the real risk of repairs down the road.

We have heard reports that some Dealers have stopped carrying the Green long life but at time of this writing it was still available from Subaru.   But knowing Subaru It won’t surprise me if it’s not available before too long.

The Blue coolant is scheduled to be changed every 100k, I believe this to be a very bad idea and suggest it every 60k instead.  If you change the coolant in an older model Subaru to the new Blue coolant, I think it’s unwise to believe the service interval can be stretched out to 100k as well, and do not think it’s worth doing.  Interestingly enough it appears that Subaru still wants the Conditioner to be put in, I find it odd that it’s not in the coolant itself at this stage.

You should not use aftermarket long life coolant like Dex Cool.  I do not suggest any form of aftermarket stop leak.

Hope that helps clear things up a bit and thanks for Reading.


106 Responses

  1. Good morning Justin,

    Thank you for all that you do for Subaru owners with your videos and articles and taking your time to answer everybody’s questions.

    I have a 2002 Subaru Legacy GT Limited 2.5 non turbo sedan with 150,000 miles.

    I just put in new 6 Star head gaskets and OEM timing components and OEM timing belt and new Subaru Long Life Green coolant and OEM Subaru thermostat.

    We’ve used the Subaru Coolant Conditioner once every year for the last several years to keep her from leaking.

    She has never run bad or overheated in the past.

    My question is due to the past Coolant Conditioner use should I now practice preventative maintenance and replace the possibly restricted radiator with a new Subaru OEM radiator or just do a complete coolant system drain and flush and replace with new Subaru green coolant?

    Again, thank you for all that you do.


    1. Hey Mark,

      I would suggest replacing the radiator when the system was opened up any thing that hit air is going to harden. Fingers crossed the heater core doesn’t also clog on you.


      1. Thank you Justin,
        Thank you for the response.
        That’s exactly what I was thinking.
        I’ll get the new Subaru radiator installed and also flush out the old heater core.
        I Appreciate all that you are doing for Subaru people.

  2. Justin, many thanks for all the helpful information. I have a 2000 Outback temperature gauge that is creeping up to the “3/4 mark” when idling but my OBD2 scan tool shows the temp as well under 200 degrees. I shut the car off after that. In the last 30 months/7k miles I have put in a genuine Subaru thermostat and a genuine Subaru engine coolant temperature sensor so those would not likely be failing so soon. Do you ever see the temp gauge itself go bad? Wiring harnesses? Fan relays? Please let me know if you have ideas on the above temperature gauge issue.

    Also, I got a Lisle spill free funnel per your recommendation but when I tried to use it on the Denso 221-3601 radiator, none of the adaptors seem to fit. The old radiator cap fit but the radiator neck looks to be shorter so I can not tighten down the B top because the B adaptor is sitting too high up in this new radiator. Any ideas would be appreciated.

    Thank you.

    1. Hey David,

      There are two possibilities. Either the gauge is Lying or the Scan tool is, because the sensor for the Scan tool and the sending unit for the gauge live about one inch from another the best test would be to obtain an infrared type thermometer that you can point at the area in the coolant crossover that houses the sending until and sensor and see what actual temps are. Once you know the answer to that question testing should resume from there. I think this type here should work fine, wont break the bank and will double as a pizza stone temp checker.

      Hope that helps point you in the next direction

  3. Hi! Just wanna say thank you for replying to these questions. I just bought a 2005 Subaru Outback a few months ago. Need to change the coolant as the engine has started overheating and the tank is bone dry. Do I use the Subaru green long life coolant or the new blue stuff? The engine was recently rebuilt with new head gaskets and a timing belt. From what I understand the engine is newer than 2005 but how new is a mystery to me. Would love some help deciding. Thank you!

    1. Hey Jaelle,

      The green coolant is what you need. Should not be out of coolant if its all been addressed. Maybe its just a hose? But an engine that is run out of coolant could be damaged.

      Hope its something simple for you


  4. Hi Justin,
    I enjoy reading your older posts, and watching your videos.
    I have a 2001 OB Ltd, 4-cyl with 150K. Head gaskets were replaced in 2013 at 82,500 miles.
    I read your response to a post, “The conditioner was a way for Subaru to potentially avoid having to warranty HG on some older models, there is not much talk of it anymore except to say we have had to deal with a lot of restricted radiators later in life as a result some times causing a HG failure. I don’t suggest it at all and truly only ever used it as we did not want to void any extended Coverage Subaru was offering to the owners of 200 to 2002 models.”
    Can you tell me more about that Extended Coverage? I never heard about that. I do recall receiving a notice about the conditioner and that was performed by the dealer at the time.

    Thanks for your time!

    1. Hello Robert,

      The WWP-99 Campaign is what you are referring to and it extended the HG warranty out for those Subaru Vehicles in a certain VIN range Subaru deemed affected, that also had the conditioner put in and maintained there after.

      A lot of Dealers would continue to add the conditioner in as a way in my opinion to increase sales on vehicles that were not affected. At the end of the day its stop leak and was really a way for Subaru to kick the can down the road. there are no cars still covered under WWP-99 it is long past expired.

      Hope that helps


  5. Getting ready to change coolant again.
    After stat is removed and maximum amount of coolant is drained – seems like the water pump would be dry.  Then after stat reinstalled and coolant added seems like it would run dry until stat opens and allows coolant in via lower radiator hose.  If this is correct – – does it hurt to run the water pump dry for the few minutes it will take for stat to open?

    1. Hey Don,

      If you fill it properly the WP should not be dry, we use a Vacuum type refill system on most post 2007 models, prior to that we would just use the coolant fill funnel and purge the air out while we filled, on some models this was done by removing the Air bleed screw at the radiator, on others we would remove a bypass hose to give air a place to escape while filling. Once coolant comes out of the open port, reinstall hose or plug and continue filling.

      Thats the best advice I have for you, I hope it helps


  6. Hey Justin,
    So my husband and I are changing our engine in our 99 Subaru legacy outback sus it’s the dohc 2.5 can we use Preston antifreeze in it once we get the new engine in it?

  7. Hi Justin,

    I don’t see anyone commenting with my year/model, so I figure I would ask … just to be 100% sure.

    I’ve got a 2009 Outback 2.5 Limited (nonturbo) H4 16V. Headgasket was replaced by previous owner, not sure if they use 6-star or not, unfortunately. :-/

    Any regular green coolant will work? Prestone/Autozone brand?
    and use NO conditioner? or might you recommend the subaru conditioner since it might not have been a 6-star gasket?

    thanks in advance!!

    1. Hi Mitch,

      I have never been a fan of the Stop leak rebranded by Subaru as cooling system conditioner. We do not use it here at all.

      Your 2009 Subaru uses the Subaru Super blue long life, and that’s really what you want to use or equivalent, which you can find and most auto parts stores, the stuff we use is only sold at the professional level and called OEM.

      Hope that helps


  8. In preparing to change AF in my 2011 Forester I viewed you most excellent video on Youtube. where you recommend removing the lower radiator hose from the thermostat housing and then remove the thermostat to quickly drain the entire system.
    Got ready to do this and found for my model I have to remove the front exhaust pipe! (Seems a little out of character for a company that puts the oil filter on top!)
    Since removing the exhaust pipe is more than I feel comfortable doing myself I suppose I am left with just draining the radiator and refilling?
    Am I missing something? Is that my best option?

    I suppose I could remove the lower radiator hose from the radiator while the engine is hot (stat open) but that seems wrong on several fronts!!

    Thanks for your advice.

    1. Hi Don,

      Your right your Model does make it more challenging, the best plan of action is to in fact remove the hose from the Radiator side.


      1. Justin,
        Looking more closely I see I can easily remove the lower radiator hose from the thermostat housing so I will do that. It’s the housing & thermostat that I cannot remove without first removing the front exhaust pipe.
        So do you suggest I do this while the engine is hot and therefore the thermostat is open? Seems like the only way to really get enough coolant out to make replacement effective (meaning that after completion I would have the highest possible new / old coolant ratio.
        Thanks again.

        1. Hey Don,

          So what we do here and really this is about not filling the area between the exhaust and it’s heat shield up with coolant that must then burn away.

          We remove the lower Rad hose @ the Rad and let it drain. Then remove the T stat housing and then then T stat, this can in fact be done with out removing the Exhaust its just a bear, we have the advantage f a hoist and nice tools such as a 10mm wobble socket and extension combo.

          Now as long as you premix your coolant to a 50/50 ratio you should not really be affecting it as you should be draining out the same.

          Hope that helps


  9. Hi Justin,

    I bought a used 2007 Outback 2.5i eight months ago. I don’t have information about previous maintenance except that everything appears well kept and in great shape according to my mechanic. I had the oil changed one month ago and they said they checked all the fluids.

    Today I noticed the coolant level is below low – I don’t see any in the reserve tank. I’ve read a lot of your posts to try to understand what to do… should I buy the green Subaru coolant from a dealer, mix it 50/50 with distilled water from the grocery store, and use that to refill? Anything I should know about mixing coolant before my first attempt?

    Thank you!

    1. Hi Erica,

      Sorry for the Delay I’ve been away on Vacation with the Family. A 50/50 mix of Green Antifreeze concentrate and distilled or at least not excessively treated water is what you need, some auto parts stores will sell a pre mix of 50/50 and that’s what I prefer you keep in your car, for the 2007 there is a Subaru Long life Coolant but given the Age I wouldn’t want you to think that’s the only thing you can use to top it off.


  10. Greetings Justin,

    Don’t know if this was answered, I just skimmed through the thread. I was able to take my 04 STI to 120k miles until my bearing finally gave way and spun(the oil was topped up just right). Anyway I’m currently in the midst with my guy doing my short block replacement. I know that my car uses the OEM forest green color coolant. Would it hurt to use the super blue coolant on this new engine? Thanks in advance.

    1. Hi Jeff,

      There is no benefit to using the Blue Coolant, it wouldn’t really change the interval for replacing the coolant on your car and that’s really the only purpose behind it.

      Id really just stick with aluminum safe green and leave it at that.


  11. Justin, wonderful service you provide for us here. After looking at several hundred of these posts I am still uncertain of the exact road to take in this situition so I’ll ask anyway. My son bought an 2002 Forrestet with 97k and zero information regarding its history. After reading some of these posts he and I became concerned about the usual issues. Currently he has no oil leaks or overheating problems and says the coolant in the overflow tank is green. He is coming to visit next week so I arranged with our local shop to have the timing set, an O.E. waterpump and an O.E. thermostat installed. I found a legitimate appearing chart online that showed the VIN range for the Forrester that puts his car in the safe zone for being built with questionable head gaskets. 1. Do you believe as we do we’ll just monitor it and hope for the best and not do HG while we’re addressing timing maint.? 2. I’m suggesting we just replace coolant with Prestone and forgo the “conditioner” at time of timing set maint. Do yo agree ? Thank you very much. David in Missouri

    1. Hi David,

      If the Head gaskets are not leaking it’s okay to just monitor them, and I would not add the Coolant conditioner either. So the Chart you refer to was under the WP-99 campaign and does not exclude you model year from developing most likely a oil leak from the head gaskets over time. All of this only applies if the HG are truly not starting to leak now

      Hope that helps


  12. Hi Justin,

    Just wanted to say I’m really grateful that you’re taking time to answer all of these questions.

    I have a 2005 Forester XS. I recently did a cooling system flush and fluid change. I used the coolant conditioner (read stop leak) on the advice of someone from a forum because my car was consuming antifreeze. I used a global extended life coolant that meets JIS K2234 standards.

    Despite burping the system, the car heats up in hot weather and while going uphill. I have to turn on the heat to full blast to cool it down. I haven’t let the needle go into the red but it’s been as far as 7/8ths up. When the car is warm, the lower and upper rad hoses are both hot which leads me to conclude that awful “coolant conditioner” has probably clogged up my radiator and it isn’t flowing as well as it used to.

    I plan on replacing the radiator and using Beck Arnley green antifreeze as the new coolant.

    What are your thoughts?

    1. Hi Matt,

      I would add a Thermostat and only an OE thermostat to the list of things to replace, and no do not add any more conditioner. Fingers crossed there is no other damage.


      1. Yup, it was the radiator. I replaced and tested the thermostat first (because it’s the cheapest) which didn’t solve the problem.

        After installing the new radiator, the car runs fine. Even torture tested it going up a long stretch of hill with the air conditioning on. Solid as a rock.

        To anyone reading this: DO NOT use the “coolant conditioner” from Subaru or any other “stop leaks in a can”.

        1. Re:Matt Zyweck

          Hey Justin-

          I am worried about a similar problem occuring. I am replacing head gaskets with the Six Star on a 2000 Legacy GT EJ25. The previous owner had added the Subaru stop leak. Now that I am switching to a Six Star, would it be worth doing a Prestone radiator flush? Just the addative with water and running, it for a few days to clean out the system. Or would that not help clean the stop leak out of the radiator, etc… It hasn’t really overheated in the past, so circulation is ok, but you know that stop leak is in there gumming things up.

          What’s your opinion?

          1. Hello Skeeter,

            I would plan on replacing the radiator, and just using a garden hose and bucket to flush out the heater core. Don’t tap into the heater hose with a T you will just create a leak later. Also make sure you replace the Thermostat with an OE Subaru one.


  13. Hi Justin,

    First off, I’ve already learned quite a bit reading your articles and previous responses on this thread – many many thanks.

    My story in a nutshell:
    – 2005 Forester XT, never had an issue up to now
    – Overheated once, mechanic (Subaru specialist) believed it was cracked top radiator tank which he replaced
    – Overheated again after one week, same mechanic replaced thermostat
    – Overheated again exactly after one week, mechanic held onto it for a few days, drove it around, to and from work, told me it would not overheat for him but next thing he would do would be replace the waterpump
    – We took our chances and after a few weeks it overheated again, this time we took it to a different mechanic who noticed the radiator hoses were loose and leaking coolant and the new thermostat was not the best model. He also did a pressure test and checked for combustion gases in the cooling system and drove the car around. All good. He showed me in the coolant reservoir that the coolant was sitting between Low and High, more towards Low but said that was okay.
    – Since then I have driven it around for a couple of hours and have noticed two things: 1. the coolant has dropped to below Low, hardly anything in the reservoir. 2. there is a small amount of coolant between the many “tabs” of the radiator that clamp down the upper tank.

    I’d appreciate your opinion on what type of coolant to use (any ethylene glycol coolant?), why you think the coolant has dropped and why it may be leaking from the upper tank though the mechanic pressure tested it. Could the upper tank cap need replacing and if so does it really need to be a genuine Subaru cap?

    Thanks a lot

    1. The cooling system needs to be pressure tested, and if no leaks are found it should be evaluated for the possibility of HG damage due to multiple overheats. Maybe the cap is in fact not sealing but that can be tested.

      I have no idea what was used for coolant so its tough to tell you what you should use, I would call the shop and ask them what they use, but most likely its just normal green ethylene glycol


  14. Hi Justin – I made the mistake of mixing some typical “green stuff” into the radiator along with the factory-filled extended life blue stuff in my new Subaru Forester 2014 Limited 2.5i, was misled by the manual stating that the main tank being at or near “Low” (with a cool engine) should be topped off while in fact it expands to well above that level when warm of course but then didn’t notice the warning about mixing coolants on the next page. The added coolant was RacePRO Prediluted 50/50 Antifreeze Coolant, says “compatible with all other coolants” etc., and composed of a mix of Ethylene/Diethylene glycol and water; I did this at around 1000 miles. Per the manual, the lifetime of the coolant is now shortened to that of the green stuff (2-3 years / 36K?). I would like to get it flushed and replaced with the Subaru Authentic Blue stuff for two reasons: the maintenance interval and because the car is new, but should I do this now (I’m now at roughly 3000 miles) or can I wait until the recommended 3750-mile oil change interval? Also, have I done any harm to my engine/raditor by using this “typical” green coolant mix?

    1. Hi JP,

      It would be better to have it serviced sooner rather than later. I know many coolants sold in aftermarket channels state they are compatible, what I have seen is gelling issues at the rad cap that prevented proper cap function.


  15. Hi:

    Thanks for your ideas.

    I have a 1997 Brighton Wagon 2.2 with 86K miles.

    If I understand regular green coolant like O’Reilly Conventional Green is fine and to forget the Conditioner.

    I read that Subaru recommends a phosphate formula. Would the Prestone or Subaru Green have more phosphate? Who makes the best green radiator fluid for my car?

    Thanks for your fine blog.

    1. Hello Elizabeth,

      For your application I think you will be just fine with the Prestone. The thing I really like is you can find it almost anywhere and the suggestion for Phosphate was post your era Subaru.

      Hope that helps


  16. I have bought a used 2011 Outback Limited and now have 32,000 miles on it. I have been noticing a antifreeze smell inside the car after I drive appx 30 miles then let it idle for a couple of minutes. Radiator is full and overflow bottle fine. What can you tell me. Thanks

  17. I went and picked up a bottle from the dealer yesterday, cost $25 after taxes. The labe has the formula data on it but not a alpha code. I’ll check a few brands etc. and see if it matches anything basic. If I find something I’ll post back.


  18. What formula is the Subaru stuff? Antifreez is made at a limited numbers of manufacturers so it has a formula code. Some cars use OAT my Volvo stuff is coded HOAT which goes into a lot of European cars which have aluminum heads. The Volvo OEM stuff from the dealer is colored a light blue like Gator Aid.

    1. Your right there are only a couple of companies that make coolant, but they make it to the buyers specifications. I try to focus on the things that are important to me and steer clear of clouding the brain with the chemical composition of each and every fluid we use.

      So to answer the question I know the basics of the make up of the coolant, but not the entire formula. You would have to do your own chemical composition test as the supplier wont be able to release that info and Subaru of Japan surely wont ever let you know, I mention SOJ as opposed to SOA as there wont be anyone at the Dealer level that cares or has a clue its just a job to them.


  19. I have a 2011 Outback with 43k miles on it and recently had to top off the coolant reservoir with a small amount. I went to the dealer and bought the longlife blue coolant which was pre-diluted and asked the parts guy about the conditioner which the manual suggests to use. He said that they don’t use the conditioner in this model and actually stopped using it in all models because of it clogging up the heater core. I plan on doing a coolant change at 60k rather than the 137,500 subaru recommends anyway but what are your thoughts on the conditioner for 11 outback and the longlife?

  20. Hi,

    I have a 2102 Impreza Sport. The last week, everytime I turn the engine off, there has been an odor coming from the hood…a slight burning smell. I decided to look under the hood and saw the coolant reservoir was below the low line. I thought maybe this was causing the smell. I wnet to a local auto supply, told them the make of car and he looked on a computer and said I needed Dexcool. I bought some 50/50 and it was orange. I topped it off to the full line. Now I read that Dexcool is wrong for my car and I don’t know what to do. Is it ok because I didn’t put all that much in? Do I need to flush the whole system? Still have the smell also.

    1. Hello Steve,

      It needs to be completely drained out and a 50/50 mix of the right antifreeze put in which is the Subaru Super blue coolant.

      Its a good idea to defer to the owners manual for a list of all fluids as a guide for the next time.

      As far as the burning smell, no idea with out seeing it.


  21. I have a 2002 Outback 2.5L with 75k miles. I was planning on doing a coolant flush and using 50/50 mix of distilled water and Prestone coolant. Prestone is stated as being silicate, phosphate, borate and nitrite fee and suitable for all cars and aluminum.

    I had the head gaskets replaced at a dealership 3 years ago and I recently asked a different dealer whether I needed to use the Subaru coolant conditioner since the head gaskets had been replaced. They said no, I didn’t need to use the conditioner just use the Subaru coolant.

    I was seeking your opinion and was wondering if there is any substantive difference between Prestone and the Subaru coolant. Also what is you view on Water Wetter as I have that and use it with distilled water in my motorcycle (most tracks don’t allow ethylene glycol coolants as they are slippery if there is a leak).


  22. I have a 2002 Outback 2.5l with 75k miles. I am planning on changing the coolant and was planning to use 50/50 distilled water and basic Prestone, which is stated to be phosphate, silicate, borate and nitrite free and have an extended life of 5 years.

    I had the head gaskets changed 3 years ago at a dealership. I asked a local dealer whether I needed the coolant additive or not given that the head gaskets had been replaced. They said that I didn’t need to use the additive just the coolant. Do you agree and is there any substantive difference between Subaru coolant and Prestone?

    Thanks for your input

  23. First off, thank you for the wealth of information available on your blog!

    I’ve recently purchased a used 2009 Subaru Forester X (the eBay dealer called it X “Premium”, but I’m not sure I can identify anything premium about it. It’s pretty basic, other than heated seats. But I digress.

    I’ve had it over a week and I’m pretty happy with it so far. It’s just over 150k miles, so we banked on the possibility of needing to take care of several maintenance items. Neither I or the dealer know anything about the previous maintenance history, though my go-to Subaru mechanic (not a dealer) replaced the brakes and seems impressed; says it looks like it was well kept. Still I’ve decided to get everything done as per Subaru’s suggested 137k mile service.

    As for coolant, I think I understand that I should be using the blue Subaru “Super Long Life” 50/50 coolant in my Forester. I’m ready to schedule the appointment for a full coolant flush service. It’s been described to me as “piping hot water jetting through the system” to remove corrosion etc.

    My questions:

    1) The flush seems like a good idea since I don’t know what coolant the previous owner used (or if he/she ever changed it).

    2) In some of these comments it sounds like you don’t like the Subaru “conditioner”. Do you like ANY conditioner? If not, why not?

    3) In what cases can/should conditioner be used?

    4) In the case of a coolant system flush, is there even a reason to add conditioner (what does it do, exactly)? Isn’t the system extremely clean after the flush? Or maybe that’s exactly the time to add conditioner?

    I could probably use a complete blog write-up on this. LOL. Any advice you can offer would be awesome!

    Thanks again for the tremendous level of care you invest in Subaru owners everywhere!

    1. Hello Clark,

      It should have the Super Blue coolant yes, but no flush. A good drain and fill is really all it needs, I would add a thermostat at that mileage and also add that if there is no record of a Timing belt add that to the “must do” list.

      The conditioner was a way for Subaru to potentially avoid having to warranty HG on some older models, there is not much talk of it anymore except to say we have had to deal with a lot of restricted radiators later in life as a result some times causing a HG failure. I don’t suggest it at all and truly only ever used it as we did not want to void any extended Coverage Subaru was offering to the owners of 200 to 2002 models.

      Some Dealers still use it, but most do not.

      Subaru does not specify a Flush in the owners manual, the concept of a flush in some cases is a way for a Dealer service department to increase revenue.

      If its a general repair shop that services everything absolutely no on them doing a flush, if the same flush machine is used to service other types of cars it could damage yours which Subaru has pointed out in numerous Tech service bulletins.


  24. HI ~

    I recently purchased a 2003 Outback 2.5 with 118,000 miles; I am thinking of adding coolant and conditioner but I have no idea if the conditioner was added before. Is it ok to add one bottle of conditioner, and do I have to use green Subaru coolant or can I go with the new blue (50/50) Subaru coolant? Thanks.

    1. Hello Nile,

      I don’t suggest using the cooling system conditioner and no the blue coolant is not compatible, and you don’t need anything that expensive anyways.

      Hope that helps.


  25. I bought a 2005 Subaru Outback XT a few months ago, and need to top off the coolant for the first time. I still have a bottle of Peak Ready Use 50/50 Prediluted Antifreeze & Coolant Liquid. It’s a conventional green formal and says it’s for use in Ford and Chrysler 2000 and earlier, GM 1995 and earlier, all makes and models 1989 and earlier, but I used it in my old 1997 Subaru Impreza. Is it okay to use that in the new car? If not, is there any particular kind or grade that I should use? Thanks.

    1. Hello Michael,

      First of all if you are topping it off only then the Peak Ready Use should be fine, but not knowing what’s in it currently makes it difficult to answer that question with 100% certainty.

      Hope that helps.


  26. I have a 2011 Outback took to dealer for oil change they contact me to say there is tran fluid in radiator then say it is wrong coolant what damages is there to engine or radiator or heater core and will flushing the system work dealer says need new hoses and radiator

  27. I just want to clarify what increment you are using.. you say every 30k or 2 years for the green coolant. Do you mean 30,000 miles which is 48,000km???


  28. hey what coolant can i use in my 2001 subaru impreza rx non turbo. hatchback. is tectaloy 60plus radiator coolant ok to use???

    1. Hello Colzy,

      Im not familiar with that coolant, You want to use an all aluminum compatible type coolant, so if the coolant you mentioned fits that description you should be just fine.


  29. Hi,

    The dealer says I have a leaking radiator drain (plug). The radiator is Subaru OEM. They tightened that plastic plug for now but say that, if it does continue to leak, the entire radiator will have to be replaced, because the plug can’t be purchased on its own. Obviously, replacing the radiator would only be a last resort…

    If the plug does continue to leak and the problem is the plug and not the drain itself, are any of the following options viable?

    1. find a plug at the junkyard
    2. find a different type of plug or bolt that fits
    3. Have a plug machined
    4. Tf the problem is not the plug, can I somehow seal the drain for good, thinking that the radiator can always be drained by removing the bottom hose.
    5. Any other options?

    Thanks so much in advance.

    1. Hello Mischa,

      The petcock or drain plug for the radiator is available, so I am not sure why the Stealer is telling you otherwise.

      Call another Dealers parts department with your info, then ask for the parts number. Than call Dealer # 1 up and ask why they cant just install the drain plug part # blank.

      If you give me your year and model info ill figure it for you just to make sure you don’t get ripped off, as that’s just plain and simple wrong information.


      1. Hi Justin,

        Thanks for the quick reply. I have a 2000 OBW with a 2.5l H4, but the radiator was replaced about 2 years ago. I had a Subaru radiator put in (45111AE00A). Perhaps this one doesn’t have a replaceable plug? I sure hope it does.

        Thanks so much again.

        1. Thats what I thought…

          Here is the part number for the bleeder screw # 45124 AC000

          You will also need the o-ring # 45128 KA000

          They may show up in the description as a bleeder screw and that’s because on older model Subaru vehicles there was a bleeder screw at the top radiator tank, and Subaru to keep things simple used the old bleeder screw as a drain plug.

          Unless the Dealer installed an aftermarket radiator without the plug this is what you will need, and if its not present they did not install a Subaru radiator.

          Hope that helps

          Let me know how it all turns out.


          1. Hi Justin,

            Thanks again for looking all this up. Ok, I finally had time to stick my head in the engine compartment. The radiator was made by Calsonic Kansei. If this is not an original Subaru part, how to best proceed? Is the dealer ‘required’ to use original Subaru parts, or are they at least required to disclose that they aren’t using original parts before they do the repairs? I don’t recall exactly the conversation, but I don’t think the issue came up. In fact, since I was trying to do everything by the book to not jeopardize an SOA contribution to my HG replacements (which I didn’t get in the end…), I’d be majorly peeved if the dealer pulled a fast one here.

          2. So, I am now thoroughly puzzled. It turns out the radiator was busted for good and had to be replaced. The dealer gave me a big discount due to the fact that they had put in a radiator made by Calsonic-Kansei before, instead of the genuine article, and said they’d put in a bona-fide Subaru radiator. I just looked, and the new radiator also says “Manufactured by Calsonic-Kansai’ on it. Is it possible that this is genuine Subaru equipment, or is that the same non-Subaru silly radiator with a non-replacable plug? What stickers are on a genuine Subaru radiator? Do I have to take the car back again?

          3. Calsonic is the OE supplier to Subaru. and there will be a drain plug at the bottom on the passenger side, with a spot for a Phillips screw driver to remove or install it.

  30. Hi. I would like to know if I need to add coolant and if so, is there a coolant at Walmart that would suffice? I have a new to me 2010 2.5 outback with 84,000 mi . I have a 200 mi drive tomorrow. When checking the coolant over flow container of a cold engine the coolant is not even at the minimum level. I am a novice about car care. Can you give some advice so that I can get the car home and to A service station?

    1. Liz,

      The Super Blue Subaru Coolant is not compatible with anything sold at Walmart and can only be purchased at the Subaru dealer, if you do not have access you need to top it off with water only for now until a time you can get the proper fluid.


  31. I have a 2004 Forester XT. I’ll be rebuilding the short block myself in a couple weeks. I’ll be using Felpro Head Gaskets and Felpro/Victor Reinz for other miscellaneous seals/gaskets. It is at 99,000 miles. Does it matter what coolant I use as long as it does not contain any phosphates?

    1. Hi Charles,

      I would encourage you to rethink the brand of gaskets you are using unless you also plan on dropping in a domestic V8 into the Subaru while you are at it, as that’s what that company is good at and not so much with the Subaru. I realize they have a popular name as they make gaskets for everything, but they don’t make the “best gaskets” for every application and thats what you want to focus on.

      Any aluminum safe, green in color coolant should suffice.


      1. What brand of head gasket would you suggest then? I would like to get a gasket set, not just the head gaskets.

  32. Justin-

    I have a 2001 OB with 160K Miles. Pretty sure it has the original Head Gaskets. It had the coolant conditioner added at 98K along with new coolant. I bought it a 130K miles. I am going to change the coolant soon. I plan on using Subaru Coolant. At $27 at my local dealer, I wonder, what is so special about it? How is it different from Prestone or Beck Arnley? Also, should I add coolant conditioner again? The Head Gaskets are holding up still. Thanks.

    1. Its a darker color of green.

      If the OE coolant and conditioner have allowed the Hg to hold up why would you want to use something else?

      We use normal green coolant on cars we have installed the six star head gaskets in, Subaru coolant during the course of a K service when the Subaru is still under warranty, and the conditioner under the same set or parameters begrudgingly.


  33. Hi, I have,subaru outback station w. 2003,the motor have a leake of antifreeze,I have spend a lot of time loocking the place from coming leake, but is imposible, find, I think, the leake is comin from a freeze plogs from the rear motor, if some one may help to me, thank

    1. Hi Emilio,

      There are no Freeze Plugs, most likely the HG is leaking at the back on the drivers side but there aree other possibilities, no one can help you with out seeing the car.


  34. Thanks Justin

    I plan on getting it all up to date asap. After that it will stay on track with the maintenance.

    Short story, I have been reading your site and looking at outbacks for a couple weeks. I found one from pa in nice shape. I’m driving it home threw the hills of pa and I come up on another outback that was pouring white smoke out the tail pipe.

    You know how I felt there for a minute. lol

    I know it’s antifreeze so I back off so my new car don’t get a bath.

    I still see them going a half a mile ahead white cloud still pouring out up over the hill. I come over the hill and there they sit, not smoking anymore because it quit.

    They waved me by, but I stopped to help. They new the gasket was going but had been driving it anyhow till this happen. They said, we didn’t stop because we were almost home.

    I think they need more then a gasket it now. Nice 2001 outback dead on the side of the road..

    On another note, there are lots of them around here. I see 10 to 20 everytime I’m out and they are all still running fine.

    Thanks again

    1. They are going to wish they hadn’t driven it into the ground and had repaired it when they could have controlled the price.

      When they get to the point that they are billowing smoke out, it is all over but the screaming and shouting.

      Take care of your Subaru and you can drive it 300,000 miles or longer if you choose, yes you will put money into it over the years but you will be money ahead if you are proactive like you are trying to be now.


  35. I just bought a 07 outback with 70,000. It was a trade in at a non Subaru dealer and the PO owner can’t be reached.

    There are no records at subaru for service so Im thinking I better change the coolent and add the conditioner.

    My question is,If this by chance was already done (which I can’t fine out) would the conditioner that I add cause a problem ?


    1. Hi Gary,

      This is a tough one to answer as to much conditioner can be problematic. I will tell you that I am not a big fan of the Conditioner as well.

      I would at this time just change the coolant, and maybe at the 90k change the coolant and add conditioner if you choose.


      1. Thanks for the reply Justin.

        I was able to contact the PO today and he did oil changes with moble 1 but never did anything else.

        He bought it used with 40,000 on it and didn’t know what the 1st owner did.

        Now that I know a litte more I guess doing the 60,000 service would be the thing to do ?


  36. Yes I am choked….not sure what to do…I called another dealer and they stated they use the super long life in every car thsy work on. They don’t even stock the generic stuff. They also stated that when they switch a vehicle over to the blue from the green, the super long life aspect is no longer…it is considered to have the logevity of the green. Thats a rip off for their customers….
    Not sure what to do now except take a chance on a brand name that claims to be ok for Subaru…..hopefully the gaskets used on my engine when it was rebuilt were OEM.

    1. Yes,

      Its almost criminal that some dealers no longer sell the Green Long life coolant, and instead use non O.E. Coolant which Subaru has stated for years is not ok.

      Its also correct that using the Blue Super Coolant doesn’t lengthen the service interval in an older Subaru either, at least they came clean on that aspect.

      Sorry to hear that something as easy as coolant has to be so difficult. I will actually Have one of my guys get an exact shipping cost for the Green coolant shipped VIs UPS Ground for you and send you an email.


      1. Thanks Justin…..yes I agree this is a pretty complicated effort to just change the coolant! Thankfully I love my Subaru (3rd one). I had a 98 Outback a few years ago and had the head gasket(s) blew on my way home from the dealership…..thankfully there was a powertrain warranty included with car and it covered the majority of the cost…though I did contribute some $$ towards the timing belt etc. while it was apart. But I do not want that to happen again! I rely on this car and being a single parent I cannot afford to have this happen just yet.
        I did call some other dealers today and was quoted $9.95 for a litre of the Super unmixed and $18 for a gallon of 50/50. That first dealer probably quoted me for a flush and fill with Super I think. It was on a Saturday and I guess the guy working the counter was just filling in and made a mistake. The dealers I called today said they recommend the Super in all years. One does not even carry the generic variety. And one of them also recommended the conditioner as well. So I am ok with buying the premix (2 jugs). $36 is reasonable for piece of mind and also knowing that it has been mixed with deionized water is a bonus as well.
        But I should not use the conditioner with blue….correct? Like I stated earlier, the gaskets were replaced 50,000 kms ago with, more than likely, non OE gaskets….

        I appreciate you getting me a quote on Long Life shipped to me….


  37. Hi again Justin…I’m back again! I called a dealer the other day and asked about the Subaru coolant. I was advised by the parts guy that they do stock it and the cost was $22 CDN. So I went there today and asked for some of the ” Subaru” antifreeze. The came back to the counter with a jug of generic stuff. I said no, the “Subaru” antifreeze. Oh the super long life…..he quoted me $88 for a jug and advised me it was premixed so 2 jugs would be needed…Holy crow!!!! Now what? I see in the original post you mentioned that dealers may not carry it anymore even though it is available. When I was at the dealer, a mechanic came to the counter and said they use the generic stuff in everything except the newer vehicles… do you sell the long life coolant? How much do you cahrge for it?


    1. Yes Subaru Of Canada seems to march to a different beat than SOA.

      In America the Subaru Dealers are typically not allowed to use Generic coolant.

      Its not realistic to ship chemicals to Canada I am afraid.

      Its really going to kill you that we charge $25.87 per gallon for the Subaru Long life (Green) and its not premixed.

      I am always amazed at what the Dealers in Canada seem to get away with.


  38. Hi Justin……first off, awesome website!!!!

    My question is in regards to my 02 OBW (2.5 SOHC) I want to change the coolant and also the thermostat before winter sets in. No problems with overheating leaks etc. Just want to do this for peace of mind. The car has 315,000 Kilometers on it but the engine was apparently rebuilt about 50,000 ago. I have no clue which brand of head gaskets were used. I am trying to find out that info through the previous owner. What coolant (50/50 mix?) should I use and should I use the Subaru Coolant Conditioner assuming I never get the info from the previous owner….Many thanks in advance

    1. Hi Michael,

      If it has the Subaru Head Gaskets installed than I would use the Subaru coolant, but At that mileage I am not sure I would suggest the conditioner.

      Do make sure however that you only buy and install a Factory Subaru Thermostat or you are just inviting disaster.


      1. Hi Justin,
        Thanks for your reply……why shouldn`t I use the conditioner? I am still striving to find out which gaskets were used….my guess is they were not OEM gaskets….should I still stick with the Subaru coolant regardless of which gaskets were used? My guess is you will say yes…LOL What is the difference between the generic coolant and the Subaru coolant?? Oh, I did purchase an OE stat!!!

        1. Spend some time reading other articles and posts and you’ll see why I don’t like Subaru stop leak. It was to get cars out of warranty only.

          If by some chance it has the 6 star gaskets then you could use any coolant. But since it’s difficult to explain how the average home gamer identifies this I would err on the side of caution and just use the Subaru long life coolant.

          Hope that helps


          1. Thanks again Justin…..

            I do have a bottle of the conditioner but I will keep it for my old Ford farm truck not the Subie!

  39. Hello, The above article does not refer to the proper antifreeze for the H6 engine. I personally have a 2003 outback with the H6 engine .
    Thanks , Brad

  40. Hello,

    Should or shouldn’t I use the subaru coolant conditioner in my subaru OBXT with EJ255 engine? Because you didn’t say about turbo engines 🙂

    1. Its really up to you. I am not a fan of clogging the radiator, and the MLS gaskets in the Turbo models hold up much better then the SOHC single layer type.


  41. I have been a reular reader for a few years. Now there is a black strip accross the web page…is it me or is this being done on purpose?

    1. Hi Gary,

      No its nothing on purpose, you are using internet Explorer 9 or IE9. There is a setting you need to change in regards to the security settings if you unable to do that you can switch to a more stable browser such as Firefox or Chrome. I don’t use IE so i cant guide you through how to do it. There are many Word press themes that have this issue, there is nothing that can be done on our end other than suggest a different browser if you cant change how our site is viewed on your end with IE9.

      Hope that helps


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