12 replies to this topic

[Richard e]

1985 998 - I am changing the heater matrix and adding new coolant. Halfords are recommending an OAT antifreeze - previously I have added ethylene glycol blue. Is the OAT okay and can I mix as not intending to replace all coolant - unless I have to to avoid incompatible mixing. I remember the coolant being green when we got the car new?

[gazza82]

Think you should stick with Glycol-based. OAT eats through the solder used in the rad construction.

But then again I'd triple check any advise Halfords give .. I've had to question a lot of their parts over the years .. incorrect bulbs, batteries, etc ..

[Spider]

I'd also strongly suggest a Glycol based coolant. It's compatible with all the materials in your cooling system, assuming it's standard.

[Lplus]

What else does OAT eat into, apart from solder?  Alloy rad and alloy/plastic heater matrix should remove the solder content.

[Quinlan minor]

Is the OAT okay and can I mix as not intending to replace all coolant - unless I have to to avoid incompatible mixing.

It’s important to know that many IAT(Glycol) and OAT coolants do not mix.

If they’re added into a cooling system together the results can be catastrophic, creating a gelatinous substance that blocks the system and causes widespread damage to internal components.

Edited by Quinlan minor, 09 September 2023 - 08:23 AM.

[Ethel]

OAT can be had with additives now that alleviate the copper 'n solder eating.

 

You could still opt for glycol on a CBA basis (whether that stands for Can't Be A....ed, or something else) when you factor in topping up (running with no expansion trap) and the benefits/probability of not having your Min in bits in 3years or less. 

[jomaoliveira79]

I am using Motul OAT green antifreeze, for more than 10 years in my minis.
Nothing wrong and never had the cooling system so clean, in fact, initially it helped to flush rust inside engine. Other advantage is that OAT antifreeze lasts many years without need to change.

[Lplus]

I believe the later minis, Mpi and maybe Spi, had the brass waterway plugs in the head changed to aluminium so that with alloy/plastic rad and heater matrix it was possible to use OAT coolants.

[Richard e]

Thanks for the replies. It’s a bit confusing really. The safest is to a) not mix and b) stick with what is in it already - assuming no problems. So, I am sticking with ethylene glycol, which is an IAT as I understand it. I am ignoring Halfords, as even to consider theirs I need to understand if the formula is solder etc safe. I wonder if the vivid green stuff in it when new (yes we have had the mini since 1985) was just green coloured ethylene glycol?

[Designer]

I use 

GS119890 - Mini anti freeze 1 litre (minispares.com)

 

As I am pretty sure they will not sell the wrong stuff for our 1988 Mini

Edited by Designer, 12 September 2023 - 05:02 AM.

[Bobbins]

Bluecol?

[gazza82]

Thanks for the replies. It’s a bit confusing really. The safest is to a) not mix and b) stick with what is in it already - assuming no problems. So, I am sticking with ethylene glycol, which is an IAT as I understand it. I am ignoring Halfords, as even to consider theirs I need to understand if the formula is solder etc safe. I wonder if the vivid green stuff in it when new (yes we have had the mini since 1985) was just green coloured ethylene glycol?

Glycol-based antifreeze was available in several colours over the years ... mainly blue but often green. Problem now is OAT is not only available in red .. but also blue and green! Hence some of the confusion out there.

I try to keep to simple in my garage .. the Blue mix is Glycol/IAT, Red is OAT. Makes it easy to grab the correct one.



And then you have waterless-coolants ...

[Lplus]

 

Thanks for the replies. It’s a bit confusing really. The safest is to a) not mix and b) stick with what is in it already - assuming no problems. So, I am sticking with ethylene glycol, which is an IAT as I understand it. I am ignoring Halfords, as even to consider theirs I need to understand if the formula is solder etc safe. I wonder if the vivid green stuff in it when new (yes we have had the mini since 1985) was just green coloured ethylene glycol?

Glycol-based antifreeze was available in several colours over the years ... mainly blue but often green. Problem now is OAT is not only available in red .. but also blue and green! Hence some of the confusion out there.

I try to keep to simple in my garage .. the Blue mix is Glycol/IAT, Red is OAT. Makes it easy to grab the correct one.



And then you have waterless-coolants ...

 

Looking at the Comma antifreezes It seems the dilutable coolants are all ethylene glycol based but the difference is the inhibitors, either silicates or OAT.  The G40 I bought which specifically says Silicate based not OAT based on the bottle is red.