How steep can it go?

[NonMember]

1 hour ago, Chris A said:

Daily attention implies that Triumph knew the Herald would evacuate coolant.

Exactly. In 1959 it was expected that car owners would perform regular maintenance checks such as topping up the coolant daily. Modern cars have to be designed for zero maintenance. That's why the cooling system design has evolved. It is most definitely not the same as a Herald.

2 hours ago, johny said:

There is basically only three types of system: open (evaporation) used very early on in vehicle design, semi closed as used on the sixes, closed like moderns and it appears the Herald...

No. The Herald is a semi-open system, expected to be lossy. The sixes were "desertised" with the bottle to be nearer to a closed system. The Dolomites had an early version of the modern style fully closed (although it didn't always work).

[johny]

But its impossible that the Herald continually loses coolant because once the coolant has expanded to its full extend ie reached its highest possible temperature, it cant expand to a greater extent the next time! On future runs the coolant just expands to fill the space it left in the radiator when it cooled the previous time and can only lose more if its temperatures goes up even higher or theres a leak...

[Pete Lewis]

on the simple systems with just an overflow i thought it was common practice not to brim the radiator you always left room for expansion with a air gap in the rad header 

as Jonny says once its done its expansion its done for good or you just end up with a mess  out the overflow every time it heats up ... point less 

Pete

 

[Chris A]

39 minutes ago, Pete Lewis said:

on the simple systems with just an overflow i thought it was common practice not to brim the radiator you always left room for expansion with a air gap in the rad header 

Yes, as both colin & i mentioned earlier, the book says the level should be 1" below the bottom of the filler neck.

In the case of my system it has recently decided that this level is too high and wants it to be just at the top of the core tubes. Maybe just because the weather at present is exceptionally hot, later in the year will see if it returns to its' previous habit.

[Pete Lewis]

you know its out there listening and determined to get you back for something else 

47 minutes ago, Chris A said:

see if it returns to its' previous habit.

 

[Colin Lindsay]

11 hours ago, johny said:

But its impossible that the Herald continually loses coolant because once the coolant has expanded to its full extend ie reached its highest possible temperature, it cant expand to a greater extent the next time! On future runs the coolant just expands to fill the space it left in the radiator when it cooled the previous time and can only lose more if its temperatures goes up even higher or theres a leak...

That sounds like how I see it, too - loss through expansion, yes, until the no-loss-point is reached through the level dropping, but there's bound to be an amount of evaporation even assuming the system is leak-free. I'll still check mine, there's a fine line between maintenance and paranoia.

As for modern cars.... no-one knows how to change oil or top up water any more. Not even the screenwash.

[johny]

If the rad cap doesnt lift once the coolant level has stabilised there shouldnt be any loss through evaporation - its effectively a closed system like a modern car. However as I say unlike the later design theres no way of knowing the level in the rad from the outside which is why Triumph recommends regular checking...

[Chris A]

1 hour ago, Colin Lindsay said:

As for modern cars.... no-one knows how to change oil or top up water any more. Not even the screenwash.

I take exception to that 😉. I do know where the screen wash filler cap is on my modern, can't remember when I last checked it. I usually do it just before we go on holiday . . .

[Badwolf]

Screen wash???   It has screen wash????

[Chris A]

1 minute ago, Badwolf said:

Screen wash???   It has screen wash????

And not just when it's raining