Thread: TD5 Coolant - Was red now it's green.....

I still run the OAT red stuff. At the moment I seam to replace it every 12 months at quite an expense.

OAT is 98% (or something like that) ethylene glycol, it's just that the inhibitor package uses some sort of carboxylic acid as it's inhibitor, whereas most of the old style 'green' dyed coolants used a silicate that coated the internal meta surfaces to inhibit.
The OAT only works where corrosion starts, hence it is a bit better than silicate based corrosion inhibitors at heat transfer as it doesn't coat everything. (claimed to be half way between conventional coolants and straight water)

OAT doesn't appear to be very tolerant of leaks or introduced air, but if the coolant system is in good shape it will last OK.

Some of the other Euro builders use a HOAT (hybrid organic acid technology) which uses a slightly different chemistry and appears a little more tolerant of problem systems.

The theory is that OAT's and HOAT's should give longer cooling system life as they are less abrasive to the water pump, etc than old style coolants and you don't suffer the silicate dropout (the dreaded sludge) that happens with the old style coolants when they have exceeded their useful life.
I tend to think that most problems people have with the OAT coolants is the use of water with too many minerals in it (eg. tap water) which battle the add package right from the outset and shortening it's life.

An excellent coolant chart for different vehicle types is here http://www.valvoline.com/zerex/pdf/Z...d=1B5D1AEA1AFC

Another thing that hasnt been said is the systm should be flushed with demineralized or distilled water completely before adding new coolant,and also only topped up withthis type of water.OAT has been in my TD5 since new & it is changed every 2 yrs no trouble so far.
We use NULON green stuff 4yr,250k in our work vans with demineralized water,and never have any trouble.

As JC has said some of the green inhibitors may be ok in the TD5,i think one of the LR specialists in Sydney also will not use OAT.


Just noticed Rick 130 said not to use tap water

Originally Posted by justinc

Thats why the rads eat themselves away and block up, 5 years is asking for trouble as there are precipitates that slowly block the rad from the bottom up and at the end of the 100,000km you'd be tossing the rad away (Ally one with plastic tanks) because it can't be rodded out without intruducing leaks. 40,000km or 2 years is a good time frame IMO.

JC

havent personally come across that particular problem yet....

OOC, are you using pure premix or self diluting

Funny how the truth comes out.The Td5 has a history of head trouble and now I can see why.Leaving the rad for 5 years is insane,as JC said it doesn't matter what coolant you use the core will block up and overheat the engine,no rad specailist would recommend that long,I don't even agree with 2 years as I do a chemical flush every 12 months and the tanks come off every second year to check the core.No wonder you see so many cars at the top of hills puffing steam. Pat

Originally Posted by George130

I still run the OAT red stuff. At the moment I seam to replace it every 12 months at quite an expense.

thats only because you usually have to replace your coolant with something else like the head, or the gearbox, or the flexplate or... hey is there anything you havent had to replace on that thing yet?

Originally Posted by PAT303

Funny how the truth comes out.The Td5 has a history of head trouble and now I can see why.Leaving the rad for 5 years is insane,as JC said it doesn't matter what coolant you use the core will block up and overheat the engine,no rad specailist would recommend that long,I don't even agree with 2 years as I do a chemical flush every 12 months and the tanks come off every second year to check the core.No wonder you see so many cars at the top of hills puffing steam. Pat

Thing is Pat that if OAT or HOAT is used right from the outset and there are no problems there shouldn't be any sludge buildup in the system and so everything should be OK for 5 years..........in a perfect world........


Another thing that should be said is that an acid flush should be used for OAT/HOAT coolants and an alkali one for conventional ones.
This is advice direct from the chemists at Tectaloy.

Originally Posted by Blknight.aus

thats only because you usually have to replace your coolant with something else like the head, or the gearbox, or the flexplate or... hey is there anything you havent had to replace on that thing yet?

ouch.