> It's pretty common to confuse overflow tanks with true "header" tanks such as
> are used on modern cars.
Alan, I rather disagree with your implications, not necessary your statements,
but ...
While it's certainly possible to have a simple "overflow" bottle as you've
described the TR4 having (wasn't this only on the 4A ?), it's also entirely
possible to have a "recovery" bottle that does act to keep the radiator
completely full of water. That was the original system on my 71 Triumph Stag
(and on my 80 Chevy and 89 Dodge). There are really only two distinctions :
1) The hose must reach near the bottom of the bottle (or have a fitting there),
so it remains submerged in the coolant in the bottle.
2) The radiator cap must have a secondary seal to the very top of the radiator
neck, so that air cannot enter.
With these two provisos, as the coolant expands, the pressure will go up until
the relief valve in the cap allows coolant to flow into the recovery bottle.
When the coolant cools back down and contracts, it will suck coolant back out of
the recovery bottle, thereby keeping the radiator and engine full of coolant.
Generally, pressurized recovery systems are found on cars where access to the
top of the radiator is limited or below the top of the engine. That does apply
to most modern cars, but trucks and vans frequently still have unpressurized
recovery systems.
Randall
|