[redbird68]

Morning all

I have a 79 TATA with Olds 403

I am cleaning up some details and trying to keep the car as original as possible.

Seems silly but I am having trouble figuring out what is the correct radiator cap and where I can buy one.

All engine pics I see on internet show a plain metal cap, 15# pressure. Our sponsor and others show a different looking cap for this model year, even say 'not correct'.

https://www.amesperf.com/parts/1300/

The car has a coolant recovery system and I want an OE appearing cap, which I think is plain metal (no decal), which works with the recovery system.

Any help is appreciated.

[Trevor78]

That's just a pretty replacement cap. I can't check right now but original was plain, no ears, something like an RC33.

[highway star]

For 1979: https://www.ebay.com/itm/30488711648...temCondition=3

[redbird68]

Thanks for quick replies guys

I will get an RC33

[Trevor78]

I'll edit that and say RC27 was original for a 403. It's what I have. I sold the RC33 to a Corvette guy. They are both 15lb closed system caps. I don't know off-hand of the differences. I thought it said on buildsheet, it simply indicates 15lb cap.

Firebird 6410427 RC27 Radiator cap NOS (1) by Ben, on Flickr


Note this in Ames ad....

*NOT LIKE THE ORIGINAL*

It looks neat though, 80's style. And the ears help to remove it. More functional, but not original if after that.

[burd]

I have 1 nos round one for sale, the one from Ames is the last design from GM. Still correct
In your pic that cap is not closed all the way. Arrow points to the hose.

[redbird68]

I never found a new RC27 that did not have the decal.
I ordered an RC33 from Zip Corvette (I have a '71)....looks identical to the RC27 except for the number designation. Good enough for me.
It seems either will work with the closed system.

Thanks again form the help guys...always much appreciated.

[redbird68]

I never found a new RC27 that did not have the decal.
I ordered an RC33 from Zip Corvette (I have a '71)....looks identical to the RC27 except for the number designation. Good enough for me.
It seems either will work with the closed system.

Thanks again form the help guys...always much appreciated.

[burd]

Hit the swaps.
This one’s going up for sale.

[Trevor78]

Double-checked....it's on tight, must have just been sitting there loosely for pic, or didn't have coolant added at time. Took it half off a did up again, those ears certainly help!

Firebird NOS RC27 radiator cap closed lined-up with tube (7) by Ben, on Flickr

Firebird NOS RC27 radiator cap closed lined-up with tube (6) by Ben, on Flickr

[burd]

The mechanics hated the round caps, prob why bumps were added.

[Warren Seale]

Originally Posted by burd

The mechanics hated the round caps, prob why bumps were added.

Weren't the bumps found on the caps prior to the RC27? The caps have been without bumps or ears ever since.