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What do I use to protect aluminum from ethylene glycol+water

I have a coolant tank, presently made of stainless steel. The diameter is 4" the height is 10". There are inflow and an outflow bosses welded to the side. There is also a boss for a sight glass. Normal operating pressure is 40 PSI, spikes to 78 PSI opens the pump bypass. Normal operating temperature is 40-50 deg C. I would like to switch to aluminum. I am considering a thick walled 4" tube with full diameter screw on caps at each end, with appropriate o-rings. One boss (out, 1/2") will move to the bottom cap, the 'in' and the sight glass will be tapped thru the tube sides, and brazed in place. whet can I use to absolutely prevent the coolant from corroding the can?

Ken Hunter

2006

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First of two simultaneous responses --

What is wrong with the SS. It should be optimal.
For aluminum, use a commercial antifreeze that specifically states that it can be used in aluminum engines. Most, but not all, do nowadays.

James Watts
Navarre, Florida
2006

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Second of two simultaneous responses --

Cooling system in modern cars is almost entirely made of aluminum (including radiator tubes, lines, pumps and engine heads). Car coolant, as you know, is a mixture of water plus a commercial antifreeze in which the main ingredient is exactly that, ethylene glycol. So, my guess is that you don't have to worry too much if you add such a product to your cooling fluid. Keep in mind that different metals (copper, brass, steel, SS) may have an adverse effect as aluminum is sacrificial to most. Rubber, plastic and the like are not threat. Certain chemicals and a low or high pH are dangerous.

Guillermo Marrufo

2006