I'm coming up on my next major service and will do a full cooling system flush. I'm looking to use the Shell Rotella ELC product. It is an ethylene glycol based product with silicates (how much? not sure). It is advertised as a fill-for-life product, with a minimum life of 300,000 miles before adding a extender that jacks up the minimum life to 600,000 miles. Compatible with conventional antifreeze.
The thing is, even with traditional antifreeze products, my antifreeze looks new after two years, and I've never had any cooling system problems. So, I figure this shell rotella, should give me that extra ooomph as my vehicle approaches middle age.
http://www.shell-lubricants.com/prod...ella_elc2.html
http://www.shell-lubricants.com/prod...RotellaELC.pdf