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2019 Premium w/eyesight
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71 Posts
Discussion Starter #1
When my motor is hot, the overflow tank coolant level is midpoint between the low and full level. Just looking for other owners coolant levels with hot motor on their new 19's. Thanks
 

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353 Posts
That's where mine was too when hot. But cold it's right on the low mark. The manual says to check cold. So I've added Super Coolant bringing it up to the full mark when cold. I'm sure it's way above the full mark now when hot but that's by design and not a problem. I wanted it full before my upcoming 6000 mile round trip out West.
 

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2012 Forester X Auto
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1,900 Posts
@rccrfan
On all Subarus (and just about every liquid cooled car) the coolant level in the overflow is only a problem if it runs out (sucking in air) or spills out (making a mess).
The minimum and maximum lines are there to provide a guide so it doesn't overflow when very hot or allow air into the system when very cold.
In temperate climate conditions you will never get even close to either of those extremes.
If the level is between the lines it is fine - That's where it is supposed to be. The overflow level itself isn't critical.
If it makes you feel better, fill it to the maximum line when the car is cold or cooled down, but the car won't care, and it won't make a difference.
On the other hand, if you notice a big drop in the level, there could be a problem, but all Subaru cars will lose some coolant over time, so not a bad idea to check it.
Coolant expands with an increase in temperature, so if you fill it to the maximum line on a hot day, it will be lower when you check it after a cold snap.
That's the way it is and it doesn't indicate a problem.
 

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2015 Forester 2.5i Limited CVT
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832 Posts
Also, the new blue Subaru super coolant can be added to the older version but not the other way around, correct?
 

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2009 Forester 2.0 XS
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239 Posts
In my old impreza (2001) there was two sets of marks , one for cold and one for hot, which IMHO is the most decent thing they could do in the first place.
 

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2012 Forester X Auto
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1,900 Posts
Most of the other fluid containers under the hood have cold and hot min and max marks, but they are also smaller reservoirs where there isn't as much tolerance.
Most probably the overflow bottle marks were for simplification, as the coolant level would otherwise need 4 sets of marks, min cold and hot, max cold and hot instead of two.
Since the level isn't critical and actually moves quite a bit during operation, they might have thought two sets would add more confusion than clarity, and in any case it isn't necessary on the overflow bottle.
If you are between the min and max lines - it's good.
Myself, I like to keep it at the max line whenever I check under the hood as it is easy to see and monitor that I'm not losing an abnormal amount of coolant, but I also don't expect it to be the same after a big temperature change, because it won't be.
 

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2020 Forester Touring Jasper Green
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109 Posts
I need to get some blue long life coolant to top off.

Is it OK to add a little distilled water in the interim? Mine came close to the low line cold with the new blue stuff. Not a big deal I know but makes me feel better to keep everything topped off after years of Subaru ownership (and amazing disappearing fluids, lol).

I already have the distilled water on hand (along with universal NAPA coolant mixed for the 05 LGT but I don't want to use that) and I figure there is more then enough antifreeze in there already that a little water wont hurt, so long as it doesn't have lots of minerals.
 

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2019 Crosstrek 2018 XT
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14,162 Posts
Do not add water. No it won't hurt but you will contaminate it. Bite the bullet or go to subaru. They should add for free
 

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2019 Forester Limited
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732 Posts
Distilled water will not contaminate, but will dilute the mix a bit. If full strength coolant is unavailable (I've only seen the 50-50 premix for sale), you've no way to bring your coolant back to a 50-50 mix.
 

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2020 Forester Touring Jasper Green
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109 Posts
Distilled water will not contaminate, but will dilute the mix a bit. If full strength coolant is unavailable (I've only seen the 50-50 premix for sale), you've no way to bring your coolant back to a 50-50 mix.
True but what’s the danger there if it is only a little bit of water? Slightly higher freezing point? A bit of a concern I admit but I doubt a couple inches in the reservoir is making much of a difference considering the total volume of the fill. More maybe would tho.

Also, what is causing the level to lower in the first place? Water is slowly evaporating presumably but the actual coolant is not going anywhere unless you have a leak. Wouldn’t it slowly get MORE concentrated over time if you only add premix? It might not be a bad idea to add a little distilled water from time to time to offset that evaporative loss. Especially if this stuff is supposed to be in there for 10 years or 136k mi. The plastic Subaru radiator barely lasts longer. Just replace both when the time comes and get your money’s worth on the super fill!

That said if you are adding a fair amount then the mix is the safe bet and that’s what I’ll likely do before I travel over the holidays. Subarus have made me OCD about fluids and the peace of mind is worth it.
 

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2019 Crosstrek 2018 XT
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14,162 Posts
I did not mean "contaminate" in the normal sense of the word. And of course if it were "necessary" to add to lo coolant, of course add water. But its not an emergency and the coolant tank is just to make sure that the radiator is 100% full. Previous generations of vehicles never had the radiator full. They really don't need to be or function. I am not suggesting you do this.

You will need the coolant eventually so just go buy it.
 

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2019 Crosstrek 2018 XT
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14,162 Posts
(y) I do know how you feel. I went through the same thoughts and at the last minute decided not to add demineralized water. Yea its expensive. :( You are not alone.
 

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2020 Forester Touring Jasper Green
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109 Posts
Just haven't been able to pick it up yet but will hit the stealership tomorrow most likely. Was thinking of getting it from Amazon but some seem to receive the green stuff instead so that scared me off. Have prime tho so can return it but just want to get it done. Stealership will get me the right stuff at least.

Sent from my SM-G973U using Tapatalk
 

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2018 Forester XT Limited CVT
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636 Posts
Distilled water will not contaminate, but will dilute the mix a bit. If full strength coolant is unavailable (I've only seen the 50-50 premix for sale), you've no way to bring your coolant back to a 50-50 mix.
The dealership will have both premix and concentrate for sale. Both seem more expensive than they should be but according to the owner's manual (2018) should last 11 years, so buy the premix for convenience, top up and leave it in the garage (cap on tight).

My overflow tank was actually empty. I hate the dealership I got the car at.
 

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2020 Forester Touring Jasper Green
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109 Posts
Picked up the long life coolant premix. Will add tomorrow, adjust TP, wash, etc. drove on highway today. Sweet ride! :D

Found the perfect sized bungie to hold up the spare tire cover so I can organize stuff in there. So much better!

Sent from my SM-G973U using Tapatalk
 
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