Found this - something to memorise to upset the chaps in Halfords... (?)
" For many years, since the demise of Methanol based antifreeze that was traditionally only added just before winter, blue/green or yellow Monoethylene Glycol (MEG) has been the mainstay of the coolant market. However Ford vehicles since 08/98 have been filled with coolant combining Monoethylene glycol with Organic Additive Technology (OAT) corrosion inhibitors.
There are important differences between standard MEG and MEG with OAT. It does not contain silicates, nitrates, nitrites, borates, phosphates or amines so that:
· Without silicates, silicate gel or "green goo" does not form.
· By eliminating phosphates, hard water scale is reduced.
· Without silicates, phosphates, nitrates, nitrites and borates, abrasive dissolved acids are greatly reduced thereby diminishing water pump seal failures.
· Without amines and nitrites, there is no potential formation of nitrosamines.
All of this results in a considerably longer life span, whilst providing improved protection of all cooling system metals, including aluminium. Benefits over conventional silicate based coolants are:
· Improved water pump life due to reduced water pump seal wear.
· Fewer abrasive dissolved solids.
· Reduced hard water scale.
· Virtually no deterioration of heat transfer capacity during service life.
· Excellent protection against high temperature and pitting corrosion.
· No silicate gel formation during storage or use.
· Effective long-term corrosion protection for aluminium, brass, cast iron, steel, solder and copper alloys.
· Long effective service life of up to 10 years or 150,000 miles.
The two types of coolant should not be mixed. Vehicles filled with MEG will have coolant coloured blue, green or yellow. MEG with OAT additives will have coolant coloured Orange (Ford) or red."
- That said the colour may not be the best guide anyway..
https://www.opieoils.co.uk/pdfs/tech-articles/coolant-antifreeze.pdf
(Starting to wonder now though if it is conspiracy to force us to drain/refill just to be sure.....)
Sorry about the hijack, probably should just have started a new thread (?)