Antifreeze types

[A500leroy]

Red or Blue whats the difference and what happens if you mix them?

[Grenadier_45]

Sadly not as simple as colour - that's just dye and not all manufacturers follow the same colour scheme. Take a look here and you'll see at least 6 major chemical formulations are in use. And you'll also see there can be more than one colour for each chemistry - OAT coolant can be orange, red, blue or green. IAT tends to be green, but HOAT (-P) is usually turquoise which might look similar to green especially when it's inside a coloured header tank.

What happens when you mix them? Usually not good - for example VW spec G11 mixed with G12 = a nasty gel which can clog the coolant passages. G12 was then followed by G12+ which was supposed to help, then G12++ (I'm not making this up) and more recently G13...

To make matters worse, other manufacturers have specified other chemistries and the Japanese tend to use different chemistry to European.

If you're not sure what's in there, the safest approach is to flush it all out and refill with the manufacturer's recommendation as even refilling with an unsuitable type can lead to internal corrosion. It's one of the reasons the manufacturers went to long-life fills that can last 10 years - no apprentices 'topping up' with the wrong stuff causing far more trouble than if they'd left it alone.

Edited by Grenadier_45 on Saturday 29th October 22:12

[A500leroy]

[trickywoo]

Prestone do a coolant that is universally compatible and has a 10 year life.

It’s widely available and a decent price.

[anonymous-user]

trickywoo said:

Prestone do a coolant that is universally compatible and has a 10 year life.

It’s widely available and a decent price.

Thanks