Aftermarket Radiator Caps Safe for Aluminum

[Scott 38530]

I have a small block C2 which won't be subjected to judging. How can you tell which aftermarket radiator caps are safe for aluminum?

[Joe L.]

Re: Aftermarket Radiator Caps Safe for Aluminum

Scott-----

I don't know if any aftermarket radiator caps, INCLUDING most of the reproductions that I've seen, are safe for aluminum. The original radiator caps for Corvettes using aluminum radiators and/or aluminum supply tanks, either the 63-67 "307" or the 68-72 RC-26, were specially insulated and designed to avoid galvanic (dis-similar metal) corrosion induced by the contact of aluminum and steel components with an electrolyte (coolant). I don't know of an aftermarket radiator cap that is made which meets this requirement. But, if you can find one that is SPECIFICALLY equivalent to the '307' or the RC-26, then you've found what you need. The reproductions that I've looked at do not have present all of the insulating elements of the '307' or RC-26.

Not to worry, though. You can still purchase an RC-26 radiator cap from Delco or GM under GM #6410206. This cap is not externally configured like the original (small ears, different script, and made of stainless steel), but it contains all of the necessary insulating elements. Functionally, it's "where it's at". You decide which is more important: form or function?

[Scott 38530]

Thanks, Joe. I'll take "Function." *NM*

[Christopher R.]

Re: Aftermarket Radiator Caps Safe for Aluminum

Joe, Do you know the pressure rating for the 6410206 cap?

[Joe L.]

Re: Aftermarket Radiator Caps Safe for Aluminum

Chris-----

Yes, it's 15 PSI. This cap can also be used for systems originally utilizing a 13 PSI cap.