Radiator cap for 1960

[Donald H.]

I just got a DeWitts direct fit 55M, which is NOT the tank top type. My 60 is a very early build, November 59 and as best I can tell never had the tank top radiator. I.e. does not have hood cut out or correct rad support.

So, given that I now have an aluminum radiator that looks just like the original copper which radiator cap should I get?

The TIM & JG references three steel and one aluminum caps. Since my car had a copper radiator, I assume it had a 7# steel cap. Or, since it is now aluminum (but looks like the copper radiator) should I use the 13# aluminum cap?

Not sure it matters, but I don't know if there is a reason to specifically use an aluminum cap on an aluminum radiator?

Thanks,

Don Harri

[Bob B.]

Re: Radiator cap for 1960

Don,

I have gone back and forth between my original and an aluminum one like yours and am back with the copper one. I didn't see any noticeable improvement in cooling, but then there was nothing wrong with my copper one. When I had the aluminum one in, I used the regular 7# cap to match the original copper radiator.

The original aluminum radiators were built to handle 13 pounds, but I'd check with DeWitt to make sure that the replacement for the copper one will first. But I think 7# would be fine unless you have an overheating problem.

I didn't like the little round nuts on the aluminum radiator. They didn't perfectly line up with the radiator frame and I broke at least two off, so be careful! If I use it again for something, I will take all of them off, realign the holes and epoxy square nuts back on it.

Let us know how it goes!

Bob

[Joe L.]

Re: Radiator cap for 1960

I just got a DeWitts direct fit 55M, which is NOT the tank top type. My 60 is a very early build, November 59 and as best I can tell never had the tank top radiator. I.e. does not have hood cut out or correct rad support.

So, given that I now have an aluminum radiator that looks just like the original copper which radiator cap should I get?

The TIM & JG references three steel and one aluminum caps. Since my car had a copper radiator, I assume it had a 7# steel cap. Or, since it is now aluminum (but looks like the copper radiator) should I use the 13# aluminum cap?

Not sure it matters, but I don't know if there is a reason to specifically use an aluminum cap on an aluminum radiator?

Thanks,

Don Harri

Don------


Personally, I would not use a radiator cap designed for a copper/brass radiator on an aluminum radiator. Such caps lack the special features designed to inhibit dissimilar metal (galvanic) corrosion. It probably would not be a big factor in deterioration of your radiator during the period that it's going to matter to you or I, but I'd still want to use a radiator cap designed for an aluminum radiator. A GM #6410206 should work just fine. This is a 13 lb cap but it's approved for your application.

For judging, if that's an issue for you, you could easily switch to a more correct appearing cap if you wish.

[Donald H.]

Re: Radiator cap for 1960

Thanks,

Joe you touched on what I was wondering, the dissimilar metal issue. I'll get the aluminum cap

[Joe L.]

Re: Radiator cap for 1960

Thanks,

Joe you touched on what I was wondering, the dissimilar metal issue. I'll get the aluminum cap

Don------


Just to be clear, the cap I mentioned is not made of aluminum. However, it is specially designed and insulated to minimize dissimilar metal corrosion when used on an aluminum radiator or aluminum supply tank.