What is the problem if your system is doing this?



I read all the comments prior to this and maybe we are discussing different systems. The stock overflow out of the radiator connects to the overflow tank. Mine is not a closed system. it still has an overflow in the recovery tank via a tube inside the tank that extends almost all the way up to the top so it won't overflow until the tank is almost full. I don't lose any water (had a very bad time with water loss in one of the cars that the tank remedied) so in my system filling the radiator all the way up is not correct. I use a regular cap as noted previously.

Unless the system is completely closed, filling the radiator all the way up is not correct in my experience.

The stainless cylindrical tanks are the best ways to go in my opinion. They look good,work good and are easy to mount. I see these Thunderbird owners with these plastic tanks and they are ugly on an otherwise nice car. Oddly enough, my TBird does not have a coolant loss problem so I never installed one in it.

54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

That coolant recovery tank does allow the cooling system itself to be completely devoid of air which is a plus on some of the newer antifreeze/coolants solutions that are being used. Some of those gel up with the inclusion of air within the system. The other advantage of a recovery tank is adding another quart of coolant to the overall system which may be just enough to keep from tipping the balance on what might be otherwise a marginal cooling system.

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And with the recovery tank in place, there is no ‘spitting’ of coolant from the system to the ground until that perfect balance or amount of expansion air finds itself on a non-tank system. On non-recovery tank systems, it’s not unusual for those vehicles to spit a small amount of fluid out after refilling the radiators to the high side until the system finds its happy balance between coolant and radiator head space.

Lorena, Texas (South of Waco)

Thanks Ted.You mentioned you are using a 7lb cap meant for a coolant recovery system.What is the actual application for that cap?Any 7lb cap for older vehicles would not work with the system because they don't have a thicker or double seal.What are you using?

  

This arrangement isn't for everyone but it is pretty much hiding in plain sight..... radiator cap is 13 psi with fresh rebuilt radiator.



At lower right is a black, one quart "JAZ" overflow bottle plumbed with the inlet at the bottom and the spit tube out the top - has no fill feature at all. I fill the radiator - topped up cold - and fully drain the bottle. The bottles have a pair of 1/4-20 tapped inserts with which to arrange a bracket - mine just has a longitudinal tab to the radiator shroud bolts. I was going to remove the upper fitting and blacken it - but never got around to it.

The first few times I ran it this way I stuck the top "spit hose" in another (Tecate) can to be sure I didn't kill the neighbors cat - but once it was established to be stable I quit doing that.

 
 Steve Metzger       Tucson, Arizona

I have a 13lb on mine now but suggestions made that I should go with a 7lb cap.Trying to find an application that uses 7lb with overflow system.Anyone have an answer?

  

Mark - Use the web and search "Stant 7 psi radiator cap" - it'll give you some numbers to start out with at the parts store.

 
 Steve Metzger       Tucson, Arizona

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.

  

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

BOB

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