Coolant level dropping & Dirty coolant
 

Hi,

Understand BRZ/86 have this coolant level droppping issue,
(quite a fair bit of discussion on coolant level from google)
On my 2017 BRZ, the coolant has dropped from exactly the Full level to Low level after 4mth of usage.
I do not observe any visual leaks or any over-heating issue.
I'm fine to top-up the coolant if there's no other side-effect.

But on my previous 3 rides (all 9yr old), 2 of them suffer from blown gasket.
So obviously i'm rather worried if this symptom of coolant dropping
is an early sign that i'm going to get another pre-mature blown gasket ?
(if they really evaporate off, does it make more sense to top-up distill water rather than coolant ?
i suppose too thick a coolant isnt that optimal, esp for a all-year summer country)

Also, there's once i sucked out some coolant as the level was an inch higher than Full after servicing.
I notice there are some sediment floating in the coolant that i sucked out.
For an old vehicle i believe this is normal,
But is this normal for a 10mth old BRZ ?

Regards !

Mine doesn't use coolant although I have seen talk of some using coolant. Whatever you do though, don't top it off with water. A little water isn't going to harm you but it's too hard to keep track of how much water you have added over time and you don't want to dilute it too much. The coolant is critical in preventing corrosion. Pure water is extremely hard on the cooling system and pump.

Oh, I reckon if you keep the coolant level in between the lines, your car will be OK.


humfrz

What evaporates is the water in the coolant, so if it's just evaporation from the overflow, distilled water is what you should add.

BUT if there are any leaks, you should add a mix of coolant and water (usually comes pre mixed).

Mine uses about half the overflow tank in a year I think. I've had to top it off twice. My coolant isn't dirty though. It should still be under warranty right? Take it to the dealer and let them deal with it (no pun intended... Originally at least ;) ).

Apparently some evaporation is “normal” for Subarus. I reported the coolant loss to the dealership when I had a WRX and the tech said that it was just evaporation from the coolant reservoir and that they all do that. Two previous Subarus that I owned (WRX and Outback) both had a small amount of coolant loss in the first 10k miles or so and I just topped it off a time or two and had no issues with either vehicle.

Keep in mind some of it is expansion and contraction too. Look at the level on a cold morning, then drive the car for a while and look again. It moves up a good ways on the reservoir.

If it mysteriously loses coolant over time, it's because the system cannot maintain pressure. There are always hot spots along the coolant path. If pressure bleeds off, those hot spots will start to sizzle and keep sizzling until the rate of boil comes to equilibrium with the rate of leakage.


If coolant loss is not accompanied with a lingering smell of antifreeze, it is almost always due to a leaky check valve in the radiator cap.

The overflow tank is vented. If coolant gets hotter than 100C, some will likely evaporate out of the vent.

Our car runs really hot, so it's normal that you see a drop in coolant lv.


Just rememeber to check it once in a while and when you have to drive long trips. 600km +

I beat the piss out of mine. I've added coolant once in five years. It's not normal to lose coolant. It is, however, acceptable to some.


I have never allowed a system to simmer off coolant.

3.5 years, same coolant.

5 years, 2 top offs, running fine

Same here.


humfrz

To quote myself: