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

Informative post, Blknight. Thanks.

I can't help but to think that adding a strap will make the electrolysis worse as there is now a good route for the electrons to move from the Aluminium to the iron.

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Originally Posted by Bohica

I can't help but to think that adding a strap will make the electrolysis worse as there is now a good route for the electrons to move from the Aluminium to the iron.

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I used to think the same,

right up until someone explained in detail how sacraficial anodes work. and other ways that might work but are harder to do.

What will cause some fun is the corrosion that will occur at the connection points.

Once the connection points are corroded then you're back to the same situation you were in before. If the connection doesnt provide a better electrical path your at the same point.

If you want to see an early example of it have a look at some early vehicles that have a bonding strap point on the radiator itself that ties the radiator to the body work and the engine.

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Originally Posted by Blknight.aus

I used to think the same,

right up until someone explained in detail how sacraficial anodes work. and other ways that might work but are harder to do.

What will cause some fun is the corrosion that will occur at the connection points.

Once the connection points are corroded then you're back to the same situation you were in before. If the connection doesnt provide a better electrical path your at the same point.

If you want to see an early example of it have a look at some early vehicles that have a bonding strap point on the radiator itself that ties the radiator to the body work and the engine.

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Interesting, I understand how sacrificial anodes work, here I'd say that the aluminium is the sacrificial anode. I don't see how you would get corrosion at the connection points as there are no copper ions to be reduced. (assuming a copper strap)

In any case the carboxylic acids are meant to stop the corrosion.
Hmm, more to think about.

if you were to do some thing like say use a stainless steel bolt on the strap to hold it to the ally block (because stainless is a really fantasticly corrosion resistant conductor) for a very short while you'd solve the problem. Right up until the stainless ate away the ally. Once the corrosion barrier is established the problem goes back to being where you dont want it to be.

the really simple version of it is...

while all the corrosion is happening somewhere else on bits you dont care about its not happening on the bits you want to protect.

were it me..

Id be putting a sensor tube in a radiator hose and using a zinc block as the contact for a low coolant alarm then as part of your cooling system service youd be required to remove and inspect the zinc block.

Of course the issue with this is as the zinc block erodes the particulate contaminate causes issues elsewhere....

Rhmm.. maybe I wouldnt do that..

you could make everything out of the same metal.. but I bags not trying to torque down a cast iron head onto a cast iron block using a cast iron gasket nor for that matter do I fancy being the one to lift in a cast iron radiator.

so we cant do that...

Aluminum block well great idea but you have to have a metal somewhat more robust to deal with the piston sliding back and forth and that tougher metal is going to cause an issue...


the only real answer is...

correct cooling system maintenance both preventative and reactive (yeah, I went there)

Funny I had very similar, had been chasing a small leak on the Defender for months, did not even look like it was coming from the hose. Got that annoyed I went around tightening clamps and guess what? Lower hose clamp had come very slightly loose, not even enough to see the leak was coming from there. Tightened and now no leak.

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Originally Posted by PhilipA

I changed from green to red (Nulon) when I changed all the hoses about 3.5 years ago in my 2002 TD5 D2.

At first all the joins /hose stubs leaked enough to leave a red line around the hoses but after about 1000Km all the leaks ceased and I have used virtually no coolant in the last 3 years.

I gild the lily a little as I had one persistent 1 teaspoon leak every 3 months leak which I thought was a delaminating hose but turned out to be a screw clamp which had jammed at a loose setting. Since replacing the hose and using OEM clamps the car has used nil.

BTW I found that the OEM spring clamps are the best to use with red coolant as they do not relax as the hose compresses. You can buy a tool to fit them for about $20. I have a tool like pliers but you can get one with a cable which would make it easier in difficult positions.
Regards Philip A
Remote Action Radiator Hose Clips Bundle Clamp Tool 18mm - 55mm Removal Tool New | eBay. I have just ordered one

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I found the article about Coolants that was in Practical Classics. Had to go back through 3 years copy's to April 2013.:o
Sorry second page is up side down , it is correct way up in my photo's.

Hello,

I read over this thread and yes it's been done to death everywhere, not just Aulro. I haven't read over the reasons for using oat coolant in the TD5 for a while but......The main reason for the use of it was due to the Alloy head and radiator.
The chunked down version(which I always like), OAT is apparently less corrosive on aluminium, nothing too technical about it really. I'm sure that someone will come up with a great long winded list of reasons, but sometimes we don't need to know 'the molecular structure interacts with etc etc etc, and then does a triple reverse with 1 1/2 twists etc etc etc'

Cheers,

Jason

As reluctant as I am to continue this done to death subject, I think a major reason for OAT is that the EC mandated against the green stuff.

OAT has a longer life than the green stuff and is reportedly less toxic.

Now the Blue stuff is available with a 10 year initial life and 5 years replacement life maybe that is the way to go.( BMW/Honda and others)

I note that Nulon is now pushing a Diesel specialised OAT. I wonder if it is just marketing or is a real advantage.

Regards Philip A