The pictured cap in the link looks to be an O.E. (original equipment) which is not suitable for a coolant recovery tank.

The coolant recovery radiator caps have double rubber seals to prevent any loss of coolant at the cap itself when the pressure point is reached. The O.E.caps for non-coolant recovery systems do not have that second seal and as a result do not work well with a coolant recovery tank. Here are pics of the 7 lb. coolant recoverycap on my ’55 but the secondary rubber seal for the top of the radiator flange in the picture blends in with the lower seal making it hard to see. But it’s there.

Lorena, Texas (South of Waco)

Wow, never realized there are so many radiator cap brands.

"The Master Cylinder"

Enjoying life at the beach in SOCAL

Seems like this is what is being discussed. Correct?

http://ww2.stant.com/modules/partLocator/view_diagram.cfm?id=10228

Jim - Erie Colorado, 1957 Country Sedan

Mark. The 7 lb. coolant recovery radiator cap on my‘55 Customline is made by MotorRad. I originally picked this one up at a radiator repair shop back in the Nineties. It was that radiator shop that clued me in to the upper radiator tank seam issue I was having with the higher pressure caps. The lower rated cap they sold me fixed that problem. The Stant cap Paul mentions should be the same.

Lorena, Texas (South of Waco)

Thank you Paul!I just did a quick search on Ebay.They are actually listed as a 10228 Stant Rad Cap.Pretty cheap too!

  

Mark,the Stant number for a double seal 7# cap is 228.

 

Paul,

Boonville,MO

I got my 7 pound double seal cap at NAPA.I'll look tomorrow and get the number for you and post it.

 

Paul,

Boonville,MO

I searched for the correct 7 lb. cap and I'd could use an answer to Mark's question also... Thanks

BOB

Steve I would have gone with the Tecate can ... drink and replace regularly ! the right way round of course.. dont drink the coolant.. though Tecate aint much better

I have seen warnings on radiators not to drink the fluid..



"Came too close to dying to stop living now!"

I can find a Stant 7lb Cap no problem BUT a lot of them are for vehicles that never used the sealed recovery system like 55-56 Ford and Thunderbirds.I know that a lot of the "add-on" systems provided a seal to use with your existing cap.So my question still is-If some of you are using a 7lb cap with the overflow bottle what is the # on the cap or what is the application for that cap.A standard 7lb cap does not will allow the full recovery of the fluid in the bottle as it cools.I have a 13lb cap with the built-in double seal and it works as it should.