Which antifreeze for a Yanmar 3YM

[lw395]

OAT antifreeze is, just like conventional low silicate antifreeze, glycol based

There are propylene and ethylene glycol antifreezes.
AIUI, some combinations of prop- and eth- with different inhibitors can be a bad idea.

Factor in not knowing what's been in there before, random other contamination etc, it can be unpredictable.
But there are coolants which claim to be compatible with everything.
Personally I think it's all cheap enough to flush out and refill with a known quantity.
For my bikes BTW, I always use de-ionised water to dilute, I don't know how much difference it makes, but it's cheap enough.

But I'm concerned that so many cooling systems seem to be designed around typical rather than 'worst case' use?

 

[VicS]

There are propylene and ethylene glycol antifreezes.
AIUI, some combinations of prop- and eth- with different inhibitors can be a bad idea.

Factor in not knowing what's been in there before, random other contamination etc, it can be unpredictable.
But there are coolants which claim to be compatible with everything.
Personally I think it's all cheap enough to flush out and refill with a known quantity.
For my bikes BTW, I always use de-ionised water to dilute, I don't know how much difference it makes, but it's cheap enough.

But I'm concerned that so many cooling systems seem to be designed around typical rather than 'worst case' use?

in the UK you'll have to go out of your way I think to find propylene glycol antifreeze for ordinary engine cooling puposes. It's used as the heat transfer medium in some food processing systems , presumably because of its low toxicity, but I guess in that case it wont be inhibited in the same way as engine antifreeze. There are also "winterising" antifreezes, for water systems mainly.

There are propylene glycol based engine cooling antifreezes both with conventional low silicate inhibitors and with OAT. but all the common readily available stuff is ethylene glycol based ITYWF.

There are universal top up mixtures and to confuse things there are hybrids and "special" formulations for various manufacturers.

 

[lw395]

https://citroenclassics.wordpress.com/category/cooling-system/

http://www.opieoils.co.uk/p-948-motul-mocool-coolant-additive-for-road-track-concentrate.aspx

From an unrelated site:
"""In contrast, here are some interesting points concerning propylene glycol (the harmless one):
•PG is metabolised by the human body into chemicals that are naturally occurring in normal, human metabolic functions. The resulting chemicals are pyruvic and lactic acids, both of which are quite normal in our bodies.
•PG is listed by the Food and Drug Administration (Yeah, that’s right. The FDA, otherwise known as the opponents to the E-cigarette industry) as GRAS (Generally Recognized as Safe).
•PG is present in some antifreeze products, but is colored pink to make it readily recognizable as non-toxic. This type of antifreeze is often found in boats and RVs.""

The use of pink to denote OAT is by no means universal it seems!!!!

 

[ThomWatt01]

However, putting OAT antifreeze in a system designed for glycol, such as in older vehicles, can cause terrible and costly damage to numerous components.

 

[Halo]

I have used Halfords O A T anti freeze in my 3YM for 12 years with no problems. Remember to empty calorifier pipe when changing and refill.

 

[ChromeDome]

The colour doesn't ensure specific properties.

More valid is the requirement stated by Yanmar for the engine:



Any brand will do as long as it is ethylene glycol based and mixed with plain water according to the manufacturer's instructions (must be mixed with water to provide anti-freeze properties - concentrated coolant will freeze before diluted!)

Since the price is similar I see no reason not to use Long-Life versions.