I just flushed my cooling system and refilled it with distilled water. I only put in a half gallon (or less) of Dex-Cool anti-freeze. I understand that pure water cools best; strengthening the anti-freeze concentration reduces heat removal properties.

Question is, what is the minimum mix I should run in the interest of protecting my water pump? Would I be better off buying some Prestone "pump lubricant and rust inhibitor"?

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'87 IROC 5.7l TPI - original owner!

 

I would not try to get by with less than about two quarts.

 

use at least 50% coolant. using less than that killed my water pump very quickly.

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'86 IROC 5-speed
305 LG4
edelbrock performer rpm intake
edelbrock 600 cfm carb
msd pro billet hei
'95 3.23 rearend
hotchkis rear suspension

 

My preference for mixture is 1 gallon of AF, the rest water. That comes out to about 70/30. Use some Red Line Water Wetter, which contains the appropriate additives; and/or something like the Prestone water pump lube and corrosion preventive product. This will give you adequate freeze protection for almost anywhere in the US (especially as far south as you are), good heat transfer, and all the necessary additives for long life of the pump, rad, etc.

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"So many Mustangs, so little time..."
ICON Motorsports

 

I use pure distilled water, plus one bottle Prestone lubricant/anti corrosive, plus 1 bottle water wetter.

I live in Florida tho..never freezes.

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"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
JSP Motorsports
ICON Motorsports