Fernox Alphi 11 Anti-freeze

[monty]

I have to confess in flushing & changing the Bluecol anti-freeze only a couple of times during the past 8000 miles & 7 years. It has always been in a 50/50 mix, always clean & showing a -25 degree protection. Never had any cooling problem in that period or indeed even over the 16+ years of ownership, with temp gauge registering around 1/2 way on average. Electric fan kicks in with standing traffic if necessary. I do understand peoples different preferences but the old fashioned system appears to have worked well for me & at a negligible cost.

[RobH]

10 minutes ago, monty said:

...during the past 8000 miles & 7 years. It has always been in a 50/50 mix, always clean & showing a -25 degree protection.

The reason for 2-year changes of conventional antifreeze is not so much because of its antifreeze performance Monty, but rather because the corrosion inhibitors become depleted in time. They are important because of the dissimilar metals present in the cooling system.

[Ian Vincent]

18 hours ago, RobH said:

The reason for 2-year changes of conventional antifreeze is not so much because of its antifreeze performance Monty, but rather because the corrosion inhibitors become depleted in time. They are important because of the dissimilar metals present in the cooling system.

So how come the corrosion inhibitors in Fernox last so much longer?

Rgds Ian

[RobH]

26 minutes ago, Ian Vincent said:

So how come the corrosion inhibitors in Fernox last so much longer?

I think you would need to ask the manufacturers about that Ian.  Maybe there are a higher percentage to start with or maybe the propylene glycol in Alphi is slower to form acids than the ethylene glycol in conventional antifreeze ?  

I can't find anything from Fernox that actually states how long it lasts - all their blurb just says 'long-term' which could mean anything, and is of course in relation to use in heating systems rather than cars.