Regardless, aren't the change times on coolants something like:
"green": 2 years
long-life "green":3-4 years
dex-cool: 5 years
Of course, I don't have a bottle of any coolant in front of me to read. I could be off by a bit. But leaving these chemicals to sit in the cooling system for more years than recommended will doubtless lead to issues. Just because you drive 8,000 miles a year doesn't mean that you should wait 4 years to change out regular "green". The chemicals "wear-out" and some may turn corrosive, chunky, etc. and are bound to eat through a gasket or some kind of metal, clog something up, or wear something out because they've lost lubricating properties.
The membership here would have a good laugh at anyone who left oil in their car for significantly longer (say, 10 years) than recommended then wondered why their car broke. I don't see how ignoring regular maintenance on the cooling system is any different.
