RC-15 radiator cap

[D S.]

I just received an original flat rivet RC-15 radiator cap with the brass pressure ring with 15# RC-15 on the left ear contained in a circle and AC on the right ear contained in a circle. Other than that it looks exactly like the ones described in Patrick Hulst's RC-15 radiator cap article in a Corvette Restorer. What is this application for?

Thanks,
Scott Sims
Texas Chapter

[Jack C.]

Re: RC-15 radiator cap

The cap is for a copper rad or a brass exp. tank. I have one on my 68 427/400 radiator. I'm sure there are other applications.

[D S.]

Re: RC-15 radiator cap

Thanks, Jack. The cap has a nice, undamaged pressure ring and the rubber seal is near perfect. I was thinking of using it on my AC equipped 1970 LS-5 but the JG only depicts the RC-15 as having the AC on the left ear and the 15# and RC-15 on the right ear. This one is reversed.

[Patrick H.]

Re: RC-15 radiator cap

Scott,

I got your e-mail and wondered if you have a picture.

FYI, I've seen other anomalies as well. I own one with an upaide down logo, for example. So, having them in reversed positions is definitely not impossible.

Patrick

[D S.]

Re: RC-15 radiator cap

Patrick, here are two photos of it:

[Mike M.]

Re: RC-15 radiator cap

Hi Scott,
Definitely an Original GM piece.
There may have been varying configurations of the stampings between the different years of production.
I'm just not involved in Sharks that much.
Hopefully, someone will chime in.
HaND

[Patrick H.]

Re: RC-15 radiator cap

Yes, from what I can see that looks real.
Don't worry about the variations.

[D S.]

Re: RC-15 radiator cap

Interesting. It has a nice, pliant rubber seal and the brass pressure ring isn't damaged. Just reverse stamping.
Thanks to all for posting.

Scott

[Jeff A.]

Re: RC-15 radiator cap

I see this anomaly all the time.
Does not seem to be a model year thing.
Here is a picture of 2 hollow rivet RC15 caps with opposite logos.

[Jeff A.]

Re: RC-15 radiator cap

found another anomaly in the early cap.
This one only has one circle.

[Peter L.]

Re: RC-15 radiator cap

While there might be some stamping configurations that are more common, I agree with Jeff that these stamping variations show up all the time and not just on RC-15s and there is no production year significance. In fact if you start looking you'll find there are a significant number of variations in these mass mass produced items like radiator caps. They made "lots" of RC-15s and they were used across the GM product line. Since the Corvette production was somewhat limited, we might not see as many different RC-15 configurations; but I have seen 6 different configurations to the stampings on RC-26s which as far as I know, the only application was the Corvette. Pete