OAT Coolant / Antifreeze

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sailswim

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there are quite a few coolant threads already and I have searched for this particular angle but not found it fully addressed.

My query is re the Organic Acid Technology in coolant

Last year I used Ethlyene Glycol which is recommended by Peachment for my Nanni engine, I just checked with them on the phone. But they didn't seem to know whether it mattered about using a coolant with Organic Acid Technology (OAT) or non-organic.

Apparently the OAT stuff is longer life coolant but I have read that it is unsuitable for older engines as it can cause problems with certain types of nylon/silicone seals. It is the default product available at a motor factors, I haven't yet looked for non-organic coolant

But does it matter?

Thanks
 
thanks Nigel

I found a relevant older thread, my initial search results on this forum weren't very relevant, but using Google instead has borne fruit -
http://www.ybw.com/forums/showthread.php?362381-Stupidly-used-OAT-coolant-for-6-years-in-a-MD2020

that thread confirms that the OAT versus IAT (inorganic/conventional) types are probably both available, but I still don't know how significant it is for me with a Nanni 3100HE (installed 2002).. looks like I need to go back to Peachment and ask again or else to Nanni directly

The colour doesn't seem to be a reliable indicator of which type of coolant (OAT or IAT).
To be clear, I am talking about ethylene glycol exclusively
 
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sailswim said:
there are quite a few coolant threads already and I have searched for this particular angle but not found it fully addressed.

My query is re the Organic Acid Technology in coolant

Last year I used Ethlyene Glycol which is recommended by Peachment for my Nanni engine, I just checked with them on the phone. But they didn't seem to know whether it mattered about using a coolant with Organic Acid Technology (OAT) or non-organic.

Apparently the OAT stuff is longer life coolant but I have read that it is unsuitable for older engines as it can cause problems with certain types of nylon/silicone seals. It is the default product available at a motor factors, I haven't yet looked for non-organic coolant

But does it matter?

Thanks
Click to expand...

Almost all engine antifreezes in the UK are ethylene glycol based .

As a rule use OAT/ advanced / long life type in newer engines if specified but for older engines it is probably better, for the reasons you state, to stick with the conventional/ low silicate type/

Most motor factor should be able to supply the conventional type. If in difficulty go to Halfords for their own brand Silicate antifreeze. If are in hard water area then buy it ready diluted.


Dont mix the OAT and conventional types. They can interact and deposit a sludge which can block your cooling system as well as making neither type of corrosion inhibitor effective
 
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I think you will find that all of the OAT coolants have been re-formulated to get around the seal problems. The liability was obvious, so they fixed it over a decade ago. Some added traces of silicone, others changed organic acids (only a few were implicated).

This is old news.

The truth is that there is no "long life" marine coolant, since the risk of seawater contamination dictates more frequent changes. Often manufactures have different service intervals list for the same engine based on whether the application is marine or land-based.
 
thanks thinwater for that information, unfortunately I hadn't come across it before

I agree that regardless of coolant type it is best to replace it every year, in addition to the risk of seawater contamination which I hadn't considered, I'm happy to take a very proactive approach to boat engine maintenance and flush out everything that is swirling around in the coolant annually

Peachment supplied further information in case anyone is interested, they use a mono-ethylene glycol (MEG) based antifreeze, which meets the technical requirements of BS6580:2010

I found 2 brands of this type in my local motor factors, as well as another type which was specifically labelled as containing "organic acid inhibitors" and did not specify the BS6580
 
sailswim said:
thanks thinwater for that information, unfortunately I hadn't come across it before

I agree that regardless of coolant type it is best to replace it every year, in addition to the risk of seawater contamination which I hadn't considered, I'm happy to take a very proactive approach to boat engine maintenance and flush out everything that is swirling around in the coolant annually

Peachment supplied further information in case anyone is interested, they use a mono-ethylene glycol (MEG) based antifreeze, which meets the technical requirements of BS6580:2010

I found 2 brands of this type in my local motor factors, as well as another type which was specifically labelled as containing "organic acid inhibitors" and did not specify the BS6580
Click to expand...

Interestingly, BS 6580 has been withdrawn, which is why newer coolants do not carry that code. The Brit standards org now relies on US standards (I'm on the US ASTM D15) for coolants.
http://www.astm.org/SNEWS/MA_2011/enright_ma11.html

Thus, the codes you are now looking for are either ASTM D3306 (probably) or ASTM D4985. The number at the end (-10) is the year of revision.

BS 6580:2010
Title Specification for corrosion inhibiting, engine coolant concentrate ("antifreeze")
Status Withdrawn
Publication Date 31 March 2010
Withdrawn Date 31 August 2015
Cross References ASTM D 1120, ASTM D 1177, ASTM D 1384, ASTM D 1881, ASTM D 3306, ASTM D 4340, ASTM D 7304, ASTM D 7437, BS EN ISO 2592, BS 2000-36, BS EN ISO 3696:1995,
 
Several reputable sources advise against using OAT coolant in any engine with brass or copper components.
Modern cars have ali radiators etc etc.

Most boat engines have copper and brass in the heat exchanger.


http://www.cgj.com/2013/05/20/what-are-the-different-types-of-antifreeze-and-can-i-mix-them/

From Opie OIls:
""Inorganic Additive Technology
This is the traditional coolant based on inorganic additives and is called inorganic additive technology (IAT). It is a tried and proven chemistry that provides a fast acting
protective film. The additives deplete and the coolant needs to be drained and replenished every couple of years. This type can be used on all mixed metal engines with
components including steel, cast iron, copper, brass, aluminium and solder without any detrimental effect
Organic Acid Technology
The newer OAT coolants work differently than the older silicate based IAT coolants. Aluminium and ferrous metals form a surface-layer of corrosion in the presence of
moisture, even with the little bit of moisture in the air. OAT coolants prevent this metal-oxide layer that protects the surface against this corrosion
Inherent with their design, the OAT coolants last longer than the older traditional IAT coolants. This category of antifreeze cannot be used in systems containing yellow
metals.
A couple of questions and answers.
Why are coolants different colours?
Coolants/antifreezes are coloured so you can visually see them; colour intensity can be an indication of over dilution. The different colours are non specific to the different
types of antifreeze. The manufacturer can dye the product any colour they want. The colour is no guide to the actual type of antifreeze type and the label should be read
before use."

http://www.machinerylubrication.com/Read/841/coolant-fundamentals
Some interesting hints about the chemistry.
 
thinwater said:
Obviously?

The ASTM limit for chloride is about 1000 times less than seawater, so even a very, very small leak is a problem.
Click to expand...

A very small leak will be a problem anyway as the coolant circuit is pressurised.
I suspect some seawater will always work past some designs of seal as the heat exchanger expands and contracts?
Is there any (DIY) way of testing for chloride at this level?
 
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