Coolant Recommendations?

[66RedFish]

I have been trying to figure out what type of antifreeze should be or can be used in my '66 225 slant six. There seems to be some concern that the modern organic acid inhibitor formulations are not compatible with the cooling systems of old cars, despite the manufacturers' claims that they are suitable for "any make, any model, any year." What about the so-called hybrid inhibitors (organic + inorganic)? Or is it best to just use the conventional (old) inorganic inhibitor coolants, assuming you can still get these?

I would be replacing the coolant every couple of years in any case, so extended life is not really a priority. I just don't want to use something that'll cause problems with seals, etc.

Steve

 

[69DARTS]

go green

 

[1970Duster]

If you have a completely new system use evans coolant, same stuff they use in NASCAR and doesn't have a boilover point

 

[LH23H2R]

You're thinking of the HOAT coolants : Hybrid Organic Acid Technology .

Basically , they're for mixed-metals engines ; and , they're great for our old(er) motors that have aluminum heads , aluminum radiators and a combination of aluminum heads with the old brass & copper radiators .

Don't wrestle with that DexCool junk though ; get the Zerex G-05 stuff , as that's what MoPar (et al. ) and Ford (et al. ) use .

There's nothing wrong with the old standby green stuff , either . It's just not -recommended- for use in new(er) vehicles ; don't mix green with gold , red , orange , etc.
Who knows ... maybe the whole "don't mix" deal is like the DOT 3 & 4 mixed with DOT 5 silicone brake fluids : no harm , really .

 

[rumblefish360]

Old school here, Peak or Prestone, works great, never an issue, 20 + years running in my Cuda, 8 years in my Magnum...etc...