undiluted antifreeze compatiable brands

Re the intervals. I was correct in that the intervals were as I posted, BUT Toyota has now doubled them! So in older printed manuals they are 5 years for first change and 3 years after. Now they are 10 years for first change and 6 years thereafter. As related to me today by Pearl's current owner, who went into the dealer to get the coolant changed and was told it wasn't required.
Note also that the older type of coolant (ethylene glycol - the green stuff) had an interval that was shorter still.

Which makes me wonder if this is purely for "environmental" reasons or actual chemical reasons (the stuff lasts that long). Hmm!?

 

Ethylene glycol is colorless and in all types of anti-freeze coolant. I think the main difference is the "Asian" formulations are silicate-free, whereas the green stuff is heavy in phosphate. Supposedly the silicates damaged seals and would leave deposits when mixed with hard water.