Thread: D2 TD5 COOLANT CONFUSION

I just had mine flushed. And I asked about the green coolant. I cant remember the brand they use. But it says OAT on side of the box. Which was good enough for me.

It may be informative to go to the Nulon site and have a look at their fact sheets. Fact Sheets- Nulon Australia

Fact sheet 101 and 114 are relevant to coolants and cooling systems.

Obviously other manufacturers also have their fact sheets. I tend to favour Nulon, so I went to their site.

The ratio that you talked about in your original posting sounds like a corrosion inhibitor ratio, which is also a green colour. I'm of the opinion that if the car comes with green, then stay with green, comes with red, stay with red, as the manufacturers warrant their engines with the coolant chosen for it and have done more extensive testing than most, however Nulon Hybrid Additive Technology stuffs up this rule!!!!

In fact, with my Hondas, I'm only going to use Honda coolant, not even Nulon, even though I have containers of it in the shed.

Landrover recommend the Red coolant with OAT (Organic Acid technology) for the very specific reason of combating internal corrosion as a result of electrolysis which comes about where different metals within the cooling system may be present.

I reviewed this matter with Nulon tech and their product Nulon Red fits well with the LR recommendation, this product based on a 30% mix with demineralized water and will not require changing for 5 years/100K.

Coolants raise the boiling point, you can however raise the mix to 50% however at these levels it is very close to reversing the benefits so 30% is about where it should be.

As for corrosive matters I replaced my water pump after 10 years (Using Nulon Red) and there isn't a blemish on any surface, a remarkable outcome.

You need to keep a close eye on your coolants and levels, this is very important with LR management, disregard it at your peril.

Looking back through the service dockets I have there was mention of an inhibitor additive on the second last service. It was 20k km ago so I'm pretty sure that's what's been in there since.
Time to change it out and I'll go and see what I can find with full OAT.
I have seen a generic test method on the coolant circuit which should see lower than 50mV while running through cycling each circuit such as lights radio etc etc. so that might be worth adopting as a periodic check in between coolant changes too. At least it may show potential bad earths on particular circuits as a side bonus. I was also wondering if a pH test would be relevant as from what I can gather and given the dissimilar metals in these circuits I'm guessing it would want to be a pretty neutral pH. Anyone know what the pH should be??
Really appreciate every ones opinions and experiences on this. Now if only I could undo that M8 turbo guard bolt I could start fixing the leak on the bloody oil cooler connector and flush the whole thing and start from fresh.

At the end of the day, RED OAT is the recommended coolant by Landrover for the TD5.
I still have the yellow collar around the top of the expansion tank that states red oat coolant only.

Hot coolant thins out more than water, and red oat will find every nook and cranny to leak or weep from.

Green is bad enough, but red seems to be worse.

The green nulon is fine for alloy, according to Nulon.
My Discovery is 12yrs old, so unless i do a full replacement of all the hoses & o'rings, plus Head gasket, i'll stick to the green.
Green lasts 3yrs vs red 5yrs.


Re the turbo guard, if you mean the Gal heat guard, you only need to undo the 2-8mm bolts near the manifold each end, plus the 10mm bolt that goes into the manifold, 10mm socket with a short extension goes into the hole facing the firewall, careful not to break it.
If it feels like it's going to break drill the 2 rivets & rivet back on when your done

The reason there is a thin plastic collar with those words on the expansion tank filler neck is merely to prevent mixing other coolant types with the OAT. If you flush fully there is no added risk in using green glycol non OAT probably less in fact . OAT eats things, leaks out anywhere it can find. Glycol is made to work in alloy head, radiator cooling systems like in a Td5. Don't ever use OAT in a copper radiator it will eat it's way out. Been using Nulon long life Green in our 2 Td5's for ever.

Originally Posted by BIG O

The reason there is a thin plastic collar with those words on the expansion tank filler neck is merely to prevent mixing other coolant types with the OAT. If you flush fully there is no added risk in using green glycol non OAT probably less in fact . OAT eats things, leaks out anywhere it can find. Glycol is made to work in alloy head, radiator cooling systems like in a Td5. Don't ever use OAT in a copper radiator it will eat it's way out. Been using Nulon long life Green in our 2 Td5's for ever.

disagree with that.....

the red oat doesnt "eat" anything (unless you're running it out of spec), what it does do is find all the bits of the cooling system that have not been maintained and lets you know about it by leaking out.

I use it exclusively in the families TD5's and used it exclusively in mine before I sold it with no problems from either side.

Its no longer a secret squirrel hard to get coolant so theres no reason not to use it....

Hmmm ,,,,okay ,,I won't try and argue with somone of your experience Dave. I guess he can read about the problems associated with OAT coolant and why HOAT (hybrid OAT) coolant was introduced himself.