Is it normal that the coolant gets low in time?

[Busybee]

Hi,

I have a 2019 limited and 14000 miles. Last month I just checked some of the liquids and realized that the coolant level was at min (cold). After driving from Boston to NY the level gets close to max (is normal when the car is heated)

Today I checked before turning on (cold) and the level was way below the min. I did drive just 5 miles and it was just close to min. It’s scares me but never had this in my previous cars. I always check the ground for any leaks (coolant oil etc) and never saw a leak.

This car has been used only for my weekly Boston - NY trips and has the 14K miles. Never pushed the car and regularly drive 60-70 MPH.

I wonder if the decrease of the coolant is normal. I had my 6K and 12K Checks at the Subaru dealer and they also did not mention anything regarding this.

I can get the oem Subaru coolant and put a little in. Just wanted to ask if there is anything to worry about.

If topping it, should I add it on a heated (and after how long driving) car?

Thanks


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[jordan7831]

Would a large temperature differential between the two data points (where you observed cold coolant levels) be great enough to account for the thermal expansion?

[86TOYO2k17]

I keep mine Just at / slightly under the full line when cold. Over time you do slowly lose some although it should not be much unless you have a leak, also if you had it checked on a hot summer day, and are now checking it and its 40 degrees colder that could also drop it a few inches down the reservoir line.
Just top it off and check it a few times before your next couple drives to see if its dropping at all.

[Tcoat]

It should never be at the full line when cold. It is an expansion tank for when it gets hot and if full when cold there is no place for it to expand to.
The coolant is a mix of water and antifreeze. The water will slowly evaporate over time and needs to be replaced periodically. If you can not see or smell it then you have no issue. Just replace the water (distilled) and carry on.

[Busybee]

Originally Posted by Tcoat

It should never be at the full line when cold. It is an expansion tank for when it gets hot and if full when cold there is no place for it to expand to.
The coolant is a mix of water and antifreeze. The water will slowly evaporate over time and needs to be replaced periodically. If you can not see or smell it then you have no issue. Just replace the water (distilled) and carry on.

Thanks. That’s what I did in the previous cars. Putting distilled water from time to time.
I already got the oem Subaru coolant. Do you think If I add the coolant it will be ok? Or should I just replace the evaporated water.


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[86TOYO2k17]

Originally Posted by Tcoat

It should never be at the full line when cold. It is an expansion tank for when it gets hot and if full when cold there is no place for it to expand to.
The coolant is a mix of water and antifreeze. The water will slowly evaporate over time and needs to be replaced periodically. If you can not see or smell it then you have no issue. Just replace the water (distilled) and carry on.

FYI from owners manual

"The coolant level is satisfactory if it is between the “F” and “L” lines on
the reservoir when the engine is cold. If the level is on or below the “L”
line, add coolant up to the “F” line.
(→P. 465)"

So it is satisfactory to be in between the F and L lines, but when filling it up it says to fill to the F line.

The reservoir has plenty of expansion space beyond the F line, if you are expanding the fluid beyond that capacity then you have other issues to worry about, like air in the system, leaks in the system, or overheating.

Although as previously stated colder weather can make it read "artificially" low, i would fill right at or just under F line at about 70 degrees, or fill about 1/3" lower per 10 degree drop but never below the L.
Or just warm coolant up to 70s and top it up to just at or under F.

[Tcoat]

Originally Posted by Busybee

Thanks. That’s what I did in the previous cars. Putting distilled water from time to time.
I already got the oem Subaru coolant. Do you think If I add the coolant it will be ok? Or should I just replace the evaporated water.


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Just replace the water. Keep the coolant for when it needs to be changed.

[Tcoat]

Originally Posted by 86TOYO2k17

FYI from owners manual

"The coolant level is satisfactory if it is between the “F” and “L” lines on
the reservoir when the engine is cold. If the level is on or below the “L”
line, add coolant up to the “F” line.
(→P. 465)"

So it is satisfactory to be in between the F and L lines, but when filling it up it says to fill to the F line.

The reservoir has plenty of expansion space beyond the F line, if you are expanding the fluid beyond that capacity then you have other issues to worry about, like air in the system, leaks in the system, or overheating.

Although as previously stated colder weather can make it read "artificially" low, i would fill right at or just under F line at about 70 degrees, or fill about 1/3" lower per 10 degree drop but never below the L.
Or just warm coolant up to 70s and top it up to just at or under F.

Thanks! I stand corrected.

[DandoX]

Both the dealer and I have by mistake overfilled my coolant a few times and everything seemed to be okay, never leaked or anything. I also have never in my 6 years of ownership added distilled water. I just top it off with 50/50 toyota stuff, around 100k I do expect to do a flush. I originally planned on getting the super awesome jackson dual radiator/oil cooler, but due to other financial strains I can no longer afford that radiator


On a side note, does anyone know if the J02 recall involves replacing the coolant? I don't think it does but seems worth asking.

[86TOYO2k17]

Originally Posted by DandoX

Both the dealer and I have by mistake overfilled my coolant a few times and everything seemed to be okay, never leaked or anything. I also have never in my 6 years of ownership added distilled water. I just top it off with 50/50 toyota stuff, around 100k I do expect to do a flush. I originally planned on getting the super awesome jackson dual radiator/oil cooler, but due to other financial strains I can no longer afford that radiator


On a side note, does anyone know if the J02 recall involves replacing the coolant? I don't think it does but seems worth asking.

In warmer climates distilled water can be fine. (Such as cali)
However coolant has additives to both increase boiling point, decrease freezing point, and prevent corrosion. Its also pretty cheap and infrequently replaced. Lots of places to save money. Personally a coolant isn’t a place I choose.

[Busybee]

Appreciate all the information in a such short time. Thanks


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[DandoX]

Originally Posted by 86TOYO2k17

In warmer climates distilled water can be fine. Personally a coolant isn’t a place I choose.

Right, which is why I have been using the Toyota 50/50 stuff. Been using the same jug for a long time, bought it years ago and still use it to this day. Not very expensive considering how infrequently I have to top it off and how long its lasted.

[Spuds]

Originally Posted by DandoX

Both the dealer and I have by mistake overfilled my coolant a few times and everything seemed to be okay, never leaked or anything. I also have never in my 6 years of ownership added distilled water. I just top it off with 50/50 toyota stuff, around 100k I do expect to do a flush. I originally planned on getting the super awesome jackson dual radiator/oil cooler, but due to other financial strains I can no longer afford that radiator


On a side note, does anyone know if the J02 recall involves replacing the coolant? I don't think it does but seems worth asking.

If they pull the engine for it, then they would have to. Unless they have a way of pulling the radiator and heater core at the same time without disconnecting any coolant lines.

[Spuds]

Originally Posted by 86TOYO2k17

In warmer climates distilled water can be fine. (Such as cali)
However coolant has additives to both increase boiling point, decrease freezing point, and prevent corrosion. Its also pretty cheap and infrequently replaced. Lots of places to save money. Personally a coolant isn’t a place I choose.

Water is going to evaporate faster, leaving more coolant than water. Need to add (distilled) water to keep it 50/50.