The most important corrosion preventer for multi-metal systems (al radiator, brass/copper heater core, iron block, etc.) is grounding. When the radiator is not well grounded to the chassis, and the other chassis parts to the frame, engine and battery is when you see a lot of corrosion due to dissimilar metals. Ground it well and keep the grounds clean. To test your grounding, use a voltmeter from your coolant (just dip the (+) probe into the coolant without touching metal) and the battery (-) terminal. You want to see zero volts or as close to it as possible. More voltage = faster corrosion. I limit my systems to 0.15 volt. There are many sources for info on complete testing such as
this one.
What coolant? Anything with corrosion inhibitors and water pump lubrication in it. Anti-freeze is good in the proper ratios. The best cooling is with straight water (if it doesn't hard-freeze in your area) with a corrosion inhibitor/pump lube additive. I use the water mix in the summer and anti-freeze in the winter, storing each in the jugs until next season. Test your coolant each year with coolant test strips. Non-silicate coolant (usually pink or orange) takes much longer to turn acidic than ethylene glycol (green) coolant, but it's more expensive for the benefit, so I usually run the green stuff and pitch it after a couple years for a fresh batch.
If you don't remember anything else, remember this - never use anything but
distilled water for your coolant mix. No excuses at $1 per gallon. The chemicals and dissolved minerals in tap water are the primary cause of corrosive damage (as it allows that voltage to move through the coolant much easier), causes deposit formation, and both are especially bad when coupled with poor grounding. There's my 3 cents.
David