I've had my '91 Honda CRX Si 22 years this week .
I've had the worst experience with failing water pumps on this vehicle than any other water cooled car I've had, they usually fail around 3 years, with coolant leaking out of the 'weep' hole in the water pump casting .
About 5 years ago I learned of a product, Water Wetter, the manufacturer claims it reduces operating temperature by modifying the cohesion characteristics of water on the metal of the engine.
You use 1 fluid ounce of additive, per quart of cooling system capacity .
It also has a lubricant of some sort in it for the water pump .
My current water pump is going on 6 years now, no leaks so far .
Can't say I see any difference as far as operating temperature goes, but it seems to have cured the early failure of the water pump .
I get it locally for around $10US for a 12 fluid ounce bottle .
I change the coolant every three years .http://www.redlineoil.com/Products.aspx?pcid=10