Thread: Green coolant in my Defender TD5 confusion

The red stuff will leak.

I know that. Have an older VW golf for the kids that keeps leaking in new places no matter what I try. OTOH I just sold my 2006 Landcruiser that was red-tight. But then they are perfect in every way. Too perfect so this Def replaces it

Originally Posted by gromit

The main toxicity comes from the ethylene glycol which is in any anti-freeze, OAT, IAT, CAT, HOAT or otherwise.

OAT, CAT, IAT, HOAT all refer to the corrosion inhibitor type. Organic Additive Technology, Conventional Additive Technology, Inorganic Additive Technology, Hybrid Additive Technology plus I'm sure there are others.
....

This terminology is only used by Nulon that I can find info on.
All other manufacturers use the acronym OAT/HOAT/etc the A stands for Acid .. ie/ Organic Acid Technology. Reason is, because that's what it is. The active component in the coolant is an acid. Proplyene glycol is an acid.

The actual toxicity of Ethylene Glycol is not the product itself, it's what happens when ingested. It gets converted into more seriously toxic compounds that are lethal. Ethylene Glycol is just something to get completely wasted on if you don't mind a bit of death afterwards!

Propylene glycol oxidises into lactic acid, so much less harmful.

Of course as Rick said, that's just the simplified version, not taking into account the metals that become incorporated into the solution over time.

I've had a bot of a peek into some of the data spec sheets, and for Aluminium applications, it seems that OAT is far more favourable than conventional coolant. Going by the service corrosion tests specs, it appears that it naturally doesn't corrode aluminium, in fact the opposite may be true in that it could cause a slight build up.

Glysantin is made by BASF and in their data sheet(s) they claim weight gain for Al and Cast Iron(and Copper).
Nulon's long life green product claims a very slight loss of Al in that coolant. (no data on the cast iron/copper effect tho).

If you're not sure exactly what you have, simple tests. Decant a small amount and slug it down.
If you get smashed, you know it's Ethyl(although very likely you won't live to tell us the result.
If you feel the need to go out and hit the local IronMan circuits, it was probably the lactic acid in the oxidised OAT that did this to 'ya

If you do decide to change to a confirmed OAT product, everyone will tell 'ya you will see leaks develop over a short time.
I warned bro of this when we did his D2, and a week later he called me panicking that there's a million coolant leaks now! Waterpump and fuel cooler started to leak. Changed, but we now know that a proper coolant is now in.

When I changed my Tdi a few years back(no idea what the green stuff was already in it tho) I also went OAT.
I did mine of a more gradual period.
I did multiple flushes on it first, rand for a short while on straight water, waiting for any additional rust to clear out.
The flushed with CEMs flush stuff, which I think helped. I ran this flush stuff for a short while before using coolant too, again, just to see what more rusty stuff would come out.
Hose down the thermostat plug produced clean water on the first water flush.
Having used the CEM flush, it definitely loosened more rust, as water/flush came out rusty brown.
Did one more flush after that again and then straight water for a short while.
Finally I then used OAT, can't recall exactly but got a bulk drum of Penrite red stuff(for mine/Bros and Dads cars tho).
Where bros TD5 leaked(like Pedro says), Tdi didn't.

Originally Posted by AK83

This terminology is only used by Nulon that I can find info on.
All other manufacturers use the acronym OAT/HOAT/etc the A stands for Acid .. ie/ Organic Acid Technology. Reason is, because that's what it is. The active component in the coolant is an acid. Proplyene glycol is an acid.

But OAT refers to the corrosion inhibitor not ethylene glycol or propylene glycol which give the anti-freeze, anti-boil characteristics. Most manufacturers use ethylene glycol as a higher percentage of propylene glycol is needed to get the same anti-freeze, anti boil figures.

I noticed that it was originally referred to as Organic 'Acid' Technology but many manufacturers have changed from using the word Acid to Additive.
Product Categories | Organic Additive Coolants | Recochem - Australia



Colin

As mentioned, colour has nothing to do with it. In Europe blue colour is more common. What is more relevant is the international standards classification:
BS 6580, ASTM D4985, ASTM D3306, and a few others. But most of these standards are behind a paywall if you want the complete chemical makeup.

For Land Rover engines BS 6580 is all that you need.