Thread: Why OAT ?

I Did a search on the forum here and found this on the Common Threads

choice of coolant for D2 radiators...


cheers Khos

its to do, more or less, with prevention of corrosion via electrolysis, the life of the coolant and assistance in prevention of current leakage through the cooling system. it also tolerates a wider temp range than most stock coolants (and by stock I mean standard ethyl glycols)

Its got a lot of advantages if you look after it but it does not like contamination or dilution. its also nasty if you exceed the concentration reccomendations of the manufacturer (of the coolant not the vehicle).


ethyl glycol typically has a storage life of 10 years and an inservice life of 2-3 tops OATs, in their concentrated form will store for 15 (allegedly, they havent been around that long so how they worked that out I dont know) and have a service life between 4-8 years.

They also have the advantage of not droping solids in the insignificant parts of your cooling system, say the radiator cores, at the rates that the ethyl glycols do.

Originally Posted by Blknight.aus

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They also have the advantage of not droping solids in the insignificant parts of your cooling system, say the radiator cores, at the rates that the ethyl glycols do.

and one of the big advantages IMO.
Everyone's heard of or seen the jelly like stuff that congeals in cooling systems, that's the silicates (corrosion inhibitors) dropping out of suspension in a conventional coolant and clogging things up.
Another major advantage is that water pump lasts a lot longer as there are no silicates or nitrates (solids) to cause erosion of the impeller and seal.

Does this stuff work well in old vehicles, and particularly ones that don't see much use? My dear old lotus only gets driven a few times a year. It has a cast iron block, alloy head and a normal radiator (copper??).

Would it be suitable and would it benefit from OAT?

Originally Posted by Captain_Rightfoot

Does this stuff work well in old vehicles, and particularly ones that don't see much use? My dear old lotus only gets driven a few times a year. It has a cast iron block, alloy head and a normal radiator (copper??).

Would it be suitable and would it benefit from OAT?

I think everything needs to be in top shape before using, and it was highly recommended to me by one of the major coolant manufacturers to use an acid based flush before using an OAT based coolant rather than the alkaline based flushes normally used.
I use OAT in the Landy and converted the Patrol to it for commonality of coolants, but I kept the old Fiat tractor conventional. Even though it has a new water pump, radiator and hoses, I wasn't game. It had often been run without water in the past and so I wasn't confident about the head gasket and how the OAT may try to clean it up. (it came off SWMBO's fathers farm)

A 'safer' alternative to straight OAT is the HOAT's (hybrid organic acid technology) particularly the GO5 version, usually sold by Valvolene.

ARE (Aluminium Radiators Engineering) won't give a warranty for damage to radiators or intercoolers caused by mixing coolants.

So particular care should be taken in flushing the system (as mentioned above) if anyone wants to change.

if your cooling system is contaminated then OAT wont do you any favors and may be harmful.

If your certain its been chemically flushed correctly then you can go for it. the OATs main reason for coming into existance was to deal with the exotic blends of metals that are starting to mix it up in cooling systems.