Question about coolant

[Tcoat]

Originally Posted by Doctorjobj

So I know that you are supposed to fill your coolant by starting the engine and letting the air work itself out of the system. My question is that with the engine running should there be coolant flowing into the overlow tank? If so is it all the time or only when the thermostat is open?

The coolant will flow in and out of the tank depending on temperature and pressure. It does not flow through the tank but in when hot and gets sucked back into system when cold.

[calic]

Originally Posted by humfrz

In addition to what said above, since you live in a warm climate, and your car just needs a cup or two to bring up the level, I would suggest you just add some distilled or demineralized water.

It will be OK......


humfrz

I would stick with the oem coolant itself. Water doesn't have the same rated life as a higher content chemical coolant. Guys who pour straight distilled water have better cooling than antifreeze, but you need to change it out every year or two to prevent corrosion. Mind you this only applies if you in an area that doesn't freeze. A little might be okay, but I eventually you have to make sure the ratios stay correct.

[humfrz]

Originally Posted by calic

I would stick with the oem coolant itself. Water doesn't have the same rated life as a higher content chemical coolant. Guys who pour straight distilled water have better cooling than antifreeze, but you need to change it out every year or two to prevent corrosion. Mind you this only applies if you in an area that doesn't freeze. A little might be okay, but I eventually you have to make sure the ratios stay correct.

The reason I was suggesting it would be OK to "top off" the coolant level with distilled or demineralized water is that a little bit of water is not going to wreck up the glycol/water balance.

* the concentrated Subaru super blue stuff is 5% water to start with.

* most of the loss of coolant is due to evaporation and the water is the first to go.

So, there .......


humfrz - @Tcoat has learnt me well .....

[notout86]

Originally Posted by humfrz

The reason I was suggesting it would be OK to "top off" the coolant level with distilled or demineralized water is that a little bit of water is not going to wreck up the glycol/water balance.

* the concentrated Subaru super blue stuff is 5% water to start with.

* most of the loss of coolant is due to evaporation and the water is the first to go.

So, there .......


humfrz - @Tcoat has learnt me well .....

The glycol component of coolant is hygroscopic. Depending on the relative humidity at the breather hole of the overflow bottle, either evaporation of the water component of the coolant or absorption by the glycol will occur.
Factors I can think of varying the relative humidity at the breather hole are ambient temperature, engine compartment temperature, ambient humidity, air flow past the hole, how long the hot and cold periods experienced by the bottle are and there may be other factors.
I know many people have never had to top up for 5 years whereas I need to every few months and put it down mainly to our average humidity is much lower than the world average. I am confident I have zero leaks (other than at that breather hole).
To minimise losses I have heat-shielded the bottle with Al foil and put some foam over the hole to soften air flow past the hole, and reduced the hole size itself. My dad's old Mazda had only a pinhole.
The overflow bottle idea is a good one but a sealed variable volume would be ideal, e.g. a bladder or piston but with a sealable opening for additions in cases of leaks. There would be zero corrosive oxygen from the air getting in and consuming certain coolant components.
I agree that for the most part top-ups with PURE water is fine but the makers play safe by stating fresh coolant in case there is a true leak and it also means fresh additives are introduced.

[Ultramaroon]

distilled or DI water is fine.


Unless there's some more volatile component mixed in there, I'm pretty sure you're just gradually increasing the concentration of the coolant if you top off with the solution. Meh.

[humfrz]

Originally Posted by notout86

The glycol component of coolant is hygroscopic. Depending on the relative humidity at the breather hole of the overflow bottle, either evaporation of the water component of the coolant or absorption by the glycol will occur.
Factors I can think of varying the relative humidity at the breather hole are ambient temperature, engine compartment temperature, ambient humidity, air flow past the hole, how long the hot and cold periods experienced by the bottle are and there may be other factors.
I know many people have never had to top up for 5 years whereas I need to every few months and put it down mainly to our average humidity is much lower than the world average. I am confident I have zero leaks (other than at that breather hole).
To minimise losses I have heat-shielded the bottle with Al foil and put some foam over the hole to soften air flow past the hole, and reduced the hole size itself. My dad's old Mazda had only a pinhole.
The overflow bottle idea is a good one but a sealed variable volume would be ideal, e.g. a bladder or piston but with a sealable opening for additions in cases of leaks. There would be zero corrosive oxygen from the air getting in and consuming certain coolant components.
I agree that for the most part top-ups with PURE water is fine but the makers play safe by stating fresh coolant in case there is a true leak and it also means fresh additives are introduced.

WOW! Maybe I shouldn't have used that popcorn emoji -

I see you have put some thought into that situation -

You must be a young fellow -




humfrz

[notout86]

Still an old fart at 76 (similar to you I believe).

[humfrz]

Originally Posted by notout86

Still an old fart at 76 (similar to you I believe).

OK, OK, I got the picture -





humfrz