Engine coolant

[R1Geezer]

Can you help settle an argument. A mate of mine thinks that modern cooling systems should not have water but coolant (??) because water corrodes the inside of he engine. I'm reasonably knowledegable in this area and I'm sure you have water + antifreeze, the combination known as coolant, up to 50/50. I dont think corrosion occurs because there is no oxygen in the cooling system (other than in the water molecules!). Can someone clear his up, thanks.

[gingejbee]

Modern cars are filled with a 50/50 mix as coolant and should be topped up with the same pre-mix so as not to dilute the concentration; this not only prevents freezing but protects against corrosion. Don't forget that there may be a mix of metals in the system which could facilitate corrosion.

[Toureman]

Antifreeze has " additives" in it which stop the corrosion in the cooling system which involves a few different metals which can interact with each other and helps prevent rust.

Coolant just means a mix of water and antifreeze mix, so all cars have water in the radiator.

[jake-the-peg]

There is almost always oxygen in water dissolved in it otherwise there would be no fish!

[R1Geezer]

yes jake what I mean is, do the conditions that cause Iron to oxidise, ie rust, exist inside an engine cooling system?

[MantaRay]

As an aside, don't use tap water when mixing coolant, use deionised water.

[AlBags]

1. Didn't answer question.
2. Partial answer but near enough : )
3. Right
4. You use de-ionised water in a battery .. no need in cooling system .. where tyhere are far more additives and metal contaminents than you would have a hope in adding with tap-water!

Someone could have used the words 'corrosion inhibitors' in addition to 'anti-freeze'.

[AlBags]

PS
There will always be corrosion without inhibitors in the fluid.
Water in system inter-acts with the various metallic contents of the engine/radiator system and the gases given off by that interaction, and will otherwise corrode the system.
Sorry .. but you are wrong.