Thread: Green V Red coolant......... which one?

If we all used Red these threads would be dead but because there is Green they are still being seen.

Originally Posted by Narangga

If we all used Red,
these threads would be dead.
But because there is Green,
they are still being seen.

Boom boom!

I had an article in one of my Practical Classics mags a while back on radiator coolent s & the pros & cons , which ones to use with what metals , old vehicles & new . I will have a look over the weekend & see if I can find it . I think I will have to loon through 3 to 4 years back issues.

Hi Dave,
Thanks for all the info, having a lower surface tension does this mean that, lets go with "OAT" and leave colour out of it, coolant has better cooling ability?

Cheers Marty

Hi Andy,
I was really a bit dubious about starting off one of these threads about a "done to death" topic. However when I pulled the plug out of the head out of this engine about six months ago the thread was very second hand to say the least. With a few prayers and a ground down tap I managed to restore the thread / plug to a leak free condition.

When I picked up the head from my head / engine reconditioning chap (who in my opinion really knows his stuff) he mentioned what looked like some electrical activity between the head and the block which had shown itself as evidence of electrolosis on the aluminium side of the head. Both around the coolant channels and the sealing rings of the head gasket. He advised me to put an additional earth strap between the head and the block, or the bodywork.

With all the connections between the head and the block such as head bolts I was wondering if this effect of electrolosis could have been caused by the coolant. Hence the thread.

I would ask that others don't discredit my head reconditioning guy, he does know his stuff, he has built several successful race engines and done gazzillions of TD5 heads, he has a very busy little one-man buisness.

Cheers Marty

Originally Posted by LandyAndy

Marty.
The cheapest and best OAT is the CAT extended life coolant.
Around $100 for 20lt premix.
It exceeds Land Rover specs.
Get a price from Westrac,and try GP1200(Jack) he is a Truck part parts manager in WA.He will be able to get you 20lt drums of synthetic oil for a TD5 cheaper than anywhere.
When I was running 2 TD5's Andy at Diesel Motors Trucks was the go for CAT OAT and Synthetic oil.
ENJOY
Andrew

Correct. I researched this a while back. The CAT ELC is a Texaco sourced product that is the same as the OEM one. I was purchasing a 4L 50:50 premix for around $18 a few years ago.

I'll back Daves Nulon recommendation. Been runnng it for 7 years. Changed it out at 5yrs when replacing the radiator (broken nipple & 11yrs old) and inside all the water galleries you could see into everything was squeaky clean.


Sent by iPhone using two tin cans and Forum Runner

Originally Posted by Nomad9

He advised me to put an additional earth strap between the head and the block, or the bodywork.

With all the connections between the head and the block such as head bolts I was wondering if this effect of electrolosis could have been caused by the coolant. Hence the thread.


Cheers Marty

Hes actually on the money..

BUT...

hes not quite there..

yes putting an extra strap on will help with slowing down corrosion inside BUT it has to provide a better electrical path between the disimilar metals than the coolant. The concept is similar to a sacraficial anode on a boat hull or outboard but is on the "other" side of the equal sign when it comes to balancing out the maths.

Where it gets really tricky is when the metals are in contact with the coolant but you cant get the strap to them. In certain configurations you can actually make the situation worse.

It will work on a td5 head because of the combination of the metals. you have aluminum copper steel and cast iron. The headbolts steel is of a higher nobility than the cast iron but doesnt suffer the problem because oil is not a great conductor and carries very little free oxygen, when installed they are installed with oiled threads and oil under the heads so there is a pre existing natural break and barrier anyway. The coolant however has none of these limits. But again you need to pick the correct combination of intermediaries for the strap AND where it goes.

Dont forget you could also in some cases make it worse because now you'll move the bit that does the sacraficing to another component and depending on what youve got you might find its the fuel cooler oil cooler heater matrix or radiator.

Originally Posted by Nomad9

Hi Dave,
Thanks for all the info, having a lower surface tension does this mean that, lets go with "OAT" and leave colour out of it, coolant has better cooling ability?

Cheers Marty

If you set each in its optimal condition AND discount a heap of variables Yes.

In the Glycol (yes I know lets not have that arguement and settle for accepting that by this I mean the traditional green coolant) OAT HOAT argument Best is a subjective term that is ultimately decided on the variables.

While OAT has slightly better cooling properties, service interval and dielectric resistance its of no use to you when you cant keep it in the cooling system.