Disappearing Coolant + White Smoke = Head Gasket Replacement

[Ultramaroon]

Originally Posted by Cal3000

Do you mean that vent screw near the firewall?

Yessir. That's it.

Originally Posted by notout86

Apart from air pockets in the cooling system it is seldom realised that fresh coolant, especially if prepared from concentrates diluted with water will contain dissolved gases from air. These gases will be driven out when the coolant is heated in the cooling system and when eventually expelled to the overflow bottle , the level will drop which may be puzzling until fully expelled.
If the water used for dilution is first boiled in a container that will not introduce minerals (e.g. use stainless steel) the gases are driven out. Cover and allow to cool so the air re-absorbed is minimised then use. The re-absorption is slow if the water is kept still.

Reducing the dissolved oxygen this way will reduce oxidation too.

A small surface area of coolant in the overflow bottle helps reduce air absorption too.

I use only distilled water but it has never occurred to me to boil it. It's an excellent point.

The only thing I would add is that it does not need to come to a full boil to expel most of the dissolved gasses. Personally, I'd just go with the bleed. It's there and it's easy.

[notout86]

We did an experiment at school. Nails were in beakers of water. One was tap water, one distilled water and one boiled distilled water. After a few days the latter were hardly rusted at all. I believe that if that beaker had been sealed against air in particular oxygen, then there would be zero rust.

[churchx]

Ultramaroon: i'm not sure it's worth using distilled water these days in modern cars. Yes, it's cheapest and has best thermal properties for cooling .. but if very possibly there are mixed metals in loop, it does nothing to prevent very possible corrosion. Hence i'd still use some antifreezes instead of just water due their anticorrosion additives/properties.

[Ultramaroon]

Originally Posted by churchx

Ultramaroon: i'm not sure it's worth using distilled water these days in modern cars. Yes, it's cheapest and has best thermal properties for cooling .. but if very possibly there are mixed metals in loop, it does nothing to prevent very possible corrosion. Hence i'd still use some antifreezes instead of just water due their anticorrosion additives/properties.

Oops. My last post was misleading. I should have said "I mix only distilled water with antifreeze."

I wholeheartedly agree with you. Also antifreeze