Types of anti-freeze

[tomt966]

How about some opinions on this. Us FABO guys have iron blocks but many use aluminum intakes or possibly radiators. Do you run ethylene glycol or the newer type antifreeze? Below is one guys opinion on the Dodgecharger.com site.

If you are running all iron parts, EG is the best choice, but because aluminum oxide and iron oxide mixed create a constantly chemically changing “soup” (this is the “sludge” that is commonly blamed on DEX), EG becomes a guaranteed failure point given time and miles. An aluminum radiator will be the first to go.

I'm running EG with an iron block and aluminum intake BUT I haven't had the car too long.

 

['68-340-S]

The sludge is from mixing the old green antifreeze with dexcool. When I was a service manager for Firestone I kept a glass jar of it I took out of a car so I could show others what happens when they are mixed. I've seen an ASE report on dex. and it must be changed @ 5yrs or 150K miles or it will pit the entire inside of a cooling system. The newer styles of coolant are "global"... they will mix with every kind and color of antifreeze. The old green stuff seems to be harder to find anymore... most of the companies are switching over to the global stuff.
As far as your intake goes, Don't worry about it. My 68 has a cast iron water pump, but starting in 69/70 small block water pumps were aluminum. 69 1/2 440 six pac's used alum. intakes ( 1970 they switched from the Edelbrock to a cast iron Mopar manifold I'm sure due to cost). As long as you change your coolant like recomended your fine.

 

[Aquick408]

It does not matter what type of coolant you use, as long as you change it frequently. All types of coolant will cause corrosion if not serviced roughly every 2 years 24k miles. What happens is similar to what was mentioned, as the coolant passes over the dissimilar metals it becomes alkaline(acidic) which is what causes the corrosion.