[Healeys] question for the fluid dynamics guys

[Oudesluys]

If I understand it correctly it is just missing its expansion tank that 
should be fitted to the 1/4" overflow pipe. Especially if the radiator 
cap is fully sealed
The air in the radiator will expand when hot thus pushing out some 
coolant, which should be collected in the expansion tank. When things 
are cooling down the fluid in the expansion tank will be sucked back 
into the radiator. The hose into the expansion tank should end near the 
bottom. Fill up the expansion tank several times to about 3/4 full and 
repeat that  untill all air is expelled from the cooling system. After 
that the expansion tank should be filled to about 1/2.
The expansion tank should have its own pressure cap of about 7-10 PSI.
Kees Oudesluijs
NL

> so, Have an old (1955) Talbot Lago in. Straight 6 twin cam, much like 
> a Jag or Aston. The radiator has a totally sealed screw on cap. About 
> 1/2" below the filler neck is an internal overflow tube of about 3/4'' 
> diameter which tapers down rapidly to 1/4'' as it exits the top tank 
> through a soldered joint about 2 inches below the entrance of the tube.
>  The car does not overheat but will always leave a puddle after shut 
> down (heat soak). now, even if the coolant level is below the coils it 
> still does this. Is this a case of steam condensation in the overflow 
> tube or is it possible that there is so much expansion as to raise the 
> coolant level several inches? This has me perplexed.. Dave