Refurbish Radiator or Replace?
Thread Starter
Heel & Toe
Joined: Mar 2011
Posts: 24
Likes: 5
From: SoCal
Race Director
Joined: May 2000
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Whenever the radiator is replaced, be sure to replace the two bottom rubber cushions and the rubber isolator at the top mount. These serve two purposes. First they provide some shock isolation. Second, and most important, they electrically isolate the radiator from vehicle ground.
If you have aluminum and iron immersed in an electrolyte and then electrically connect them you have a galvanic cell - otherwise know as a battery.
Electrical isolation from vehicle ground is important for all radiator materials, and aluminum is very sacrificial, more so than copper or brass when combined with iron, and will rapidly corrode. That's what causes those pinhole leaks and seepage.
With proper electrical isolation and a modern anti-freeze product (like Zerex G-05) mixed in a 50-70 percent proportion with distilled water and changed at least every five years regardless of mileage, a new DeWitts radiator should last at least several decades.
The reason to used distilled rather than tap water is to prevent the introduction of any unwanted ions that may deplete the corrosion inhibitors in the antifreeze and cause other problems. Domestic tap water often has a small amount of chlorine - not necessary enough to detect with you nose, but they are there and corrosive to cooling system components. Also, most tap water has calcium ions, which often combine with negative ions and precipitate out as solids that can clog radiator tubes and increase thermal resistance to heat transfer.
At about a buck a gallon it's foolish not to use distilled water.
It's amazing how long these radiators last despite often indifferent maintenance, and a few originals are still around, but likely living on borrowed time.
The Harrison Aluminum radiator in my SWC began to show evidence of seepage in the mid seventies despite biennial coolant changes. I always knew that the top was loose, and after buying an AIM about that time realized that the top mount rubber isolator was not installed at St. Louis. Having learned about galvanic cells and the electromotive force series in high school chemistry, I immediately understood why it failed so soon.
I bought a new replacement from GM, which were still available through service parts in that era.
Duke
If you have aluminum and iron immersed in an electrolyte and then electrically connect them you have a galvanic cell - otherwise know as a battery.
Electrical isolation from vehicle ground is important for all radiator materials, and aluminum is very sacrificial, more so than copper or brass when combined with iron, and will rapidly corrode. That's what causes those pinhole leaks and seepage.
With proper electrical isolation and a modern anti-freeze product (like Zerex G-05) mixed in a 50-70 percent proportion with distilled water and changed at least every five years regardless of mileage, a new DeWitts radiator should last at least several decades.
The reason to used distilled rather than tap water is to prevent the introduction of any unwanted ions that may deplete the corrosion inhibitors in the antifreeze and cause other problems. Domestic tap water often has a small amount of chlorine - not necessary enough to detect with you nose, but they are there and corrosive to cooling system components. Also, most tap water has calcium ions, which often combine with negative ions and precipitate out as solids that can clog radiator tubes and increase thermal resistance to heat transfer.
At about a buck a gallon it's foolish not to use distilled water.
It's amazing how long these radiators last despite often indifferent maintenance, and a few originals are still around, but likely living on borrowed time.
The Harrison Aluminum radiator in my SWC began to show evidence of seepage in the mid seventies despite biennial coolant changes. I always knew that the top was loose, and after buying an AIM about that time realized that the top mount rubber isolator was not installed at St. Louis. Having learned about galvanic cells and the electromotive force series in high school chemistry, I immediately understood why it failed so soon.
I bought a new replacement from GM, which were still available through service parts in that era.
Duke
Thread Starter
Heel & Toe
Joined: Mar 2011
Posts: 24
Likes: 5
From: SoCal
Whenever the radiator is replaced, be sure to replace the two bottom rubber cushions and the rubber isolator at the top mount. These serve two purposes. First they provide some shock isolation. Second, and most important, they electrically isolate the radiator from vehicle ground.
If you have aluminum and iron immersed in an electrolyte and then electrically connect them you have a galvanic cell - otherwise know as a battery.
Electrical isolation from vehicle ground is important for all radiator materials, and aluminum is very sacrificial, more so than copper or brass when combined with iron, and will rapidly corrode. That's what causes those pinhole leaks and seepage.
With proper electrical isolation and a modern anti-freeze product (like Zerex G-05) mixed in a 50-70 percent proportion with distilled water and changed at least every five years regardless of mileage, a new DeWitts radiator should last at least several decades.
The reason to used distilled rather than tap water is to prevent the introduction of any unwanted ions that may deplete the corrosion inhibitors in the antifreeze and cause other problems. Domestic tap water often has a small amount of chlorine - not necessary enough to detect with you nose, but they are there and corrosive to cooling system components. Also, most tap water has calcium ions, which often combine with negative ions and precipitate out as solids that can clog radiator tubes and increase thermal resistance to heat transfer.
At about a buck a gallon it's foolish not to use distilled water.
It's amazing how long these radiators last despite often indifferent maintenance, and a few originals are still around, but likely living on borrowed time.
The Harrison Aluminum radiator in my SWC began to show evidence of seepage in the mid seventies despite biennial coolant changes. I always knew that the top was loose, and after buying an AIM about that time realized that the top mount rubber isolator was not installed at St. Louis. Having learned about galvanic cells and the electromotive force series in high school chemistry, I immediately understood why it failed so soon.
I bought a new replacement from GM, which were still available through service parts in that era.
Duke
If you have aluminum and iron immersed in an electrolyte and then electrically connect them you have a galvanic cell - otherwise know as a battery.
Electrical isolation from vehicle ground is important for all radiator materials, and aluminum is very sacrificial, more so than copper or brass when combined with iron, and will rapidly corrode. That's what causes those pinhole leaks and seepage.
With proper electrical isolation and a modern anti-freeze product (like Zerex G-05) mixed in a 50-70 percent proportion with distilled water and changed at least every five years regardless of mileage, a new DeWitts radiator should last at least several decades.
The reason to used distilled rather than tap water is to prevent the introduction of any unwanted ions that may deplete the corrosion inhibitors in the antifreeze and cause other problems. Domestic tap water often has a small amount of chlorine - not necessary enough to detect with you nose, but they are there and corrosive to cooling system components. Also, most tap water has calcium ions, which often combine with negative ions and precipitate out as solids that can clog radiator tubes and increase thermal resistance to heat transfer.
At about a buck a gallon it's foolish not to use distilled water.
It's amazing how long these radiators last despite often indifferent maintenance, and a few originals are still around, but likely living on borrowed time.
The Harrison Aluminum radiator in my SWC began to show evidence of seepage in the mid seventies despite biennial coolant changes. I always knew that the top was loose, and after buying an AIM about that time realized that the top mount rubber isolator was not installed at St. Louis. Having learned about galvanic cells and the electromotive force series in high school chemistry, I immediately understood why it failed so soon.
I bought a new replacement from GM, which were still available through service parts in that era.
Duke
