Coolant level drops

[Joeescape63]

I have a 2021 Subaru crosstrek with only 31600 miles and I noticed that the coolant level drops after I have filled it up to the full mark after the car is stone cold.Temperature is set at 68 degrees inside car while driving.I don’t see any coolant on the ground.I drive 40 miles a day.I’m thinking of having it pressure tested.
Another thing I noticed that since this car was new the blue temp light will stay on but after it goes off and I put the heat on the temp light will come on and stay on for 10 seconds.This happens when it’s cold out side but not in the summer.No codes found

 

[Furious]

Being a Subaru it could very well have a head gasket failure.

Bring it to the dealer for warranty.

 

[Rand]

I have a 2021 Subaru crosstrek with only 31600 miles and I noticed that the coolant level drops after I have filled it up to the full mark after the car is stone cold.Temperature is set at 68 degrees inside car while driving.I don’t see any coolant on the ground.I drive 40 miles a day.I’m thinking of having it pressure tested.
Another thing I noticed that since this car was new the blue temp light will stay on but after it goes off and I put the heat on the temp light will come on and stay on for 10 seconds.This happens when it’s cold out side but not in the summer.No codes found

How much are we talking here? its an open system the cap isnt sealed on the reservoir. all mine have needed maybe 8oz yearly.
1995,2011,2013,2015 (maybe 2022)

 

[MSCH]

I have a 2021 Subaru crosstrek with only 31600 miles and I noticed that the coolant level drops after I have filled it up to the full mark after the car is stone cold.Temperature is set at 68 degrees inside car while driving.I don’t see any coolant on the ground.I drive 40 miles a day.I’m thinking of having it pressure tested.
Another thing I noticed that since this car was new the blue temp light will stay on but after it goes off and I put the heat on the temp light will come on and stay on for 10 seconds.This happens when it’s cold out side but not in the summer.No codes found

honestly, coolant levels fluctuate with changes in temperature...and liquid expands when it gets hot... until you get to the point where you need to add coolant I suspect you are worrying about nothing.

 

[incognito_2u]

Pressure test? How does the Coolant recovery tank look while the engine is running?
Is it “ Bubbling up” While idling?

 

[baelzebeard]

How often do you need to add coolant?

My car loses about a cup of fluid per year. Just going under the "fill" line when we get our first sub freezing temps. I assume that much is not enough to worry about. But more frequently, I might worry.

 

[yowps3]

I've noticed that the level will always drop from full and hold off from dropping further when between 3/4 of L & F

Must be a design with modern vehicles.

 

[kschachn]

I have a 2021 Subaru crosstrek with only 31600 miles and I noticed that the coolant level drops after I have filled it up to the full mark after the car is stone cold.Temperature is set at 68 degrees inside car while driving.I don’t see any coolant on the ground.I drive 40 miles a day.I’m thinking of having it pressure tested.
Another thing I noticed that since this car was new the blue temp light will stay on but after it goes off and I put the heat on the temp light will come on and stay on for 10 seconds.This happens when it’s cold out side but not in the summer.No codes found

Are you supposed to fill it to the full mark when cold? On my vehicles that is the high level when hot. You fill it to the "cold" mark when cold.

 

[demarpaint]

When the engine is warm the coolant level rises in the recovery tank, when it's hot it goes higher, when it's cold it drops. To make it simple make sure the radiator is full, and the level in the recovery tank is at the cold mark. Then look at the coolant in the recovery tank when the engine is cold and parked on level ground each morning after it was driven the day before. That cold level should remain the same for several months, or longer, if that level gets lower you have a leak. At that point pressure test the cooling system. That will tell you for sure if you have a leak or not. Then bring it in for repair or hunt the leak down and fix it.

 

[John105]

Are you supposed to fill it to the full mark when cold? On my vehicles that is the high level when hot. You fill it to the "cold" mark when cold.

I believe this is wrong. Min max full etc is cold. When hot, it goes above. I learned only 4 years ago that coolant high hot, high cold, look for collapsed upper radiator hose and faulty cap. Hard to find this info on the web, but it happened 2x on my wife’s GM.

Imho loss of coolant is the worst symptom, even worse than oil which so many mfgs now say adding between changes is normal.

At the same time, yes, with open systems eventually a top off would be needed. I would venture a guess, annually, ie too small to notice.

When I bought the 2006 LS430 in 2016, there was zero coolant in the reservoir and zero to be seen in the radiator, yet vehicle never overheated. Still, I was paranoid I had a problem. Well it’s 2023, 7 years and 57k miles later (did not drive 2020) and no issues.

This supports that coolant evaporates in open systems. Nobody incl Lexus dealers bothered to do anything in the 9.5 years before I got the car. Toyota SLLC has its first interval done at 10 years and the coolant reservoir is inaccessible and barely viewable. Fascinating these were not important to Japanese design but a .26 cd was. Very different thinking when compared to Germans.

My .02