Corrosion rad caps

[johnbuckley]

Any suggestions as to how to minimise corrosion of the lugs of 30/31 rad caps? You can see how I've bodged a couple of these to get a few thousand more miles from each one. There must be a better way. Surely?

[Kurt in NJ]

antifreeze 50 -50 with water?
or are you using something else.

[nkaminar]

Do not use sea water in your radiator.

[johnbuckley]

antifreeze / water 30/70% . Of course when the engine is warm they are enveloped in steam and when the engine is cold they are in air ... a perfect way for rusting things

[1crosscut]

Use a 50/50 mixture.

[JoeCB]

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soluble oil, ie water pump lube and water - 65 years and no corrosion

Joe B

[katy]

I've been driving for 70 years and never saw that problem. Probably as others suggested 30/70 antifreeze/water might be the reason, We always used 50/50 because it was necessary.

[Gary WA]

Originally Posted by johnbuckley

Any suggestions as to how to minimise corrosion of the lugs of 30/31 rad caps? You can see how I've bodged a couple of these to get a few thousand more miles from each one. There must be a better way. Surely?

distilled water and a rust inhibitor. after you flush out system. I would remove gaskets and bead blast caps.

[mcgarrett]

Remove the loose rust with a wire wheel or by hand, clean with lacquer thinner and paint the the steel portion on the underside of the cap with POR 15. It would be worth a try since the plating is long gone and POR 15 is a tough, protective coating that adheres to rusty metal.

[Synchro909]

I've always run soluble oil in my cooling system (well, the car's system) and have had the same issue.

[400A]

I've not see this problem before. I use distilled water and water soluble oil (water pump lubricant). I also have used POR15 on the inside of the caps and that certainly seems to slow down any rusting. For the last few years I have been running the reproduction Eaton radiator caps on my driver cars and saving the original caps for show cars. The repop caps look fine and they seem to be holding up well with regard to rusting on the inside.

[Bigsnapper43]

I think the question was how to repair the rusted ears in the old caps. Am I wrong?

[1crosscut]

I think it was how to minimize the corrosion.

I've always used a 50/50 mix of coolant and distilled water and have never had a problem with rust or rust damage. I've seen lots of rust damage from others using different types of coolant.

[MARKA]

I also run 50 /50 anti freeze and have never had any corrosion on the cap internals

[johnbuckley]

Originally Posted by Bigsnapper43

I think the question was how to repair the rusted ears in the old caps. Am I wrong?

My primary question is how to prevent it happening to any new cap, plus now a subsequent question is any way to repair the caps in the picture to get further mileage from them !

[nkaminar]

I don't think there is any practical way to repair them. You could take them apart and stamp out new parts and then reassemble them. but not a practical solution.

A two-part epoxy paint will protect new ones, but also run 50/50 antifreeze coolant.

[Bob Bidonde]

This is my practice. The POR-15 has been on my original radiator caps for many years without any adhesion issues.