Green coolant in my Defender TD5 confusion

[Parker]

I'm baffled. maybe someone knows about this.

I bought my 2006 Def not long ago. Has service record. I called people who worked on it. Seems that is has had green coolant for at least a very very long time.

My previous 1998 TDi Def also had green coolant. Both have similar mixed metal engine arrangements. I have read up on green/red and spoken with various people. EU regs seem to be the reason for LR changing to red. Seems to me that there is no technical/metal/hose issue at all not to have green coolant.

Or is there?

[alien]

Colour isn’t a real indicator of the type of coolant, a TD5 engine should have an OAT coolant which last I checked was available in red and green.

[Parker]

My Tdi had Nulon green which is not OAT. I assume (but can't be certain) that the green coolant in my TD5 is non-OAT green Nulon. The question still remains, if it has been there for a very very long time then what?

OAT and non-OAT both have corrosion inhibitors. TDi and TD5 are mixed metal. I have found nothing to say that a non-OAT does not protect as well as a OAT. BUT, there is info that the non-OAT is EU directive compliant pointing to toxicity or similar environmental reasons for cars in the EU switching to OAT coolants. My question was about potential damage and, if so, if it is wise to change and why.

[Tombie]

Different silicate and nitrate contents in the fluids.

Very briefly (and loosely). One works by applying a coating to the surfaces which better protects from electrolytic reactions and is better suited to Aluminium rather than copper.

There are also benefits from cavitation perspective with regards to water pumps etc

[Parker]

Yes, but does it warrant a flush and change? And, since this green stuff has been in there for a long time am I inviting trouble by changing?

[Tombie]

Not really. I know several running conventional coolant.

Up to you really [emoji6]

[Parker]

Ok that’s the end for me. To now 8 people have told me not to worry and just keep it as it is. My conclusion is this: it’s about EU regulations and both types provide protection. If a green coolant TDi can live a long and happy life then it’s good enough for a TD5.
Thanks folks!

[4runnernomore]

Ok that’s the end for me. To now 8 people have told me not to worry and just keep it as it is. My conclusion is this: it’s about EU regulations and both types provide protection. If a green coolant TDi can live a long and happy life then it’s good enough for a TD5.
Thanks folks!

remember coolant is cheap overall.

replace it once a year if it’s not technically correct and you shouldn’t have an issue.

thats what I was doing with my D2.


cheers 🍻 Chris

[gromit]

My Tdi had Nulon green which is not OAT. I assume (but can't be certain) that the green coolant in my TD5 is non-OAT green Nulon. The question still remains, if it has been there for a very very long time then what?

OAT and non-OAT both have corrosion inhibitors. TDi and TD5 are mixed metal. I have found nothing to say that a non-OAT does not protect as well as a OAT. BUT, there is info that the non-OAT is EU directive compliant pointing to toxicity or similar environmental reasons for cars in the EU switching to OAT coolants. My question was about potential damage and, if so, if it is wise to change and why.

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.
As mentioned, colour mean nothing, it's just the dye they use. Would have been nice if there was a standard and the colours actually told you what type of corrosion inhibitor was used.

The main advantage of OAT corrosion inhibitors is their life, I think manufacturers changed to OAT to get longer life between changes.
The original anti-freeze used silicates and had a relatively short protection life (2-3 years).
Early OAT coolants were problematic with older vehicles (due to the materials used in the cooling system), now solved and the newer type is often referred to as OAT type 2.

I'm not sure how the different corrosion inhibitors react with each other so the best advice is to flush well before changing.
You need to mix at the correct ratio to get the best corrosion protection and the corrosion protection reduces with time hence the need to change at the manufacturers recommended intervals.

It's been pointed out to me that 'you don't need anti-freeze in Australia', correct but the ethylene glycol also raises the boiling point (as does the pressure in the system). I actually use a corrosion inhibitor in several vehicles that are not in regular use.

Back to the original question, as long as you flush out the old coolant you could use any type as long as it's mixed in the correct ratio and changed at the recommended interval.
As to the EU regs forcing the change to OAT? Never heard that one before.


Colin

[rick130]

OAT and HOAT also have better heat transfer compared to silicate based coolant, as well as the longer life.
The better heat transfer is a result of not having silicate coat all the internal surfaces.
Silicate based coolant need more frequent changing as it suffers from silicate dropout, which can result in partial blockages in the cooling system, and can also be a little more abrasive on pump seals.

Propylene glycol based coolant (food grade) is available, (Cummins/Fleetguard cooolants for example) but it's heat transfer ability isn't quite as good as ethylene glycol.
Also, it's still considered toxic after use due to picking up heavy metals from the engine castings.

[gromit]

With a lot of products the labeling doesn't even let you know what corrosion inhibitor type is used. It took a number of emails to manufacturers a few years back to get details.
I thought I was using CAT when in fact it was HOAT.

Colin

[Pedro_The_Swift]

The red stuff will leak. [wink11]

[Parker]

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 :)

[AK83]

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 [bigrolf]

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.

[gromit]

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 (http://www.recochem.com.au/index.php/products/automotive_coolants/subcategory/organic_additive_coolant/)



Colin

[Old Farang]

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.

[gromit]

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.

Or the equivalent Australian Standard, AS 2108-2004, again behind a paywall.

Just remembered, Bluecol was 'the' antifreeze to use in the UK (blue colour ?) and was original fill for most manufacturers including Land Rover.
Bluecol - Anti Freeze (http://www.bluecol.co.uk/products/anti-freeze-page/)

I see that they now have red (OAT) as well as blue. Interesting to see that their OAT is not recommended for Classic or Vintage vehicles


Colin