A catch tank doesn't have to be pressurised to have its contents returned to
the cooling system as the engine cools, it just needs the type of cap that
has two seals and the overflow pipe positioned between them, and the other
end of the pipe should reach the bottom of the tank. AFAIK UK, at least,
caps have been this way for years. I have recently fitted a catch tank to
my factory V8 because it has a relatively small expansion tank given the
size of the cooling system. When hot (or as hot as I dare remove the cap)
the coolant will be close to the top of the tank but when fully cooled will
only be an inch from the bottom. However I have never lost any coolant from
the roadster, which has no expansion tank or catch tank, but then am inch or
so of clearance for the full width of the rad gives quite a lot of expansion
for a relatively small water system.
PaulH.
----- Original Message -----
From: Larry Hoy <larryhoy@prodigy.net>
To: <mgs@autox.team.net>
Sent: Tuesday, April 04, 2000 3:36 PM
Subject: RE: coolant recovery
> > In my 1977 Midget there seem to be TWO recovery bottles. One is
apparently
> > used to fill the radiator, because there is no pressure cap on the
radiator
> > itself. If the first bottle overflows it goes into the second bottle.
> >
> > Allen Hefner
>
> This is the difference between a catch tank and a recovery tank (expansion
tank).
>
> A catch tank, or bottle, is just that, it catches the overflow of
expanding coolant. This coolant
> is not returned to the radiator. This type tank generally doesn't have a
radiator cap and is not
> pressurized.
>
> A recovery tank, or expansion tank, catches expanding coolant and returns
it to the radiator as
> the coolant cools. This type of tank generally has a radiator cap and is
pressurized.
>
> You may have either type or both.
>
> In Allen's case the first tank is a recovery tank, the second tank is a
catch tank.
>
> Larry Hoy
>
|