Another important component of our cooling system.
Our vehicles have a 14 LB cap fitted from new and should always be replaced with the same rating.
Why do we have pressurised system, well one reason is it raises our boiling point of coolant and in our very hot summer climate that can only be good.
Every 1 + LB raises boiling point by about 3 degrees F, so in theory this would equate to an increase of around 42 degrees F, bringing it to approx. 250 degrees instead of 212 degrees F.
This explains why when new we didn’t have overheating problems like the other cars.
In my early Valiant days – late 1960’s I never had an overheating problem even on 40 degrees C + plus days but saw a multitude of the other two makes with bonnets up and clouds of steam spewing out.
However, I did on several occasions have fuel vaporisation problems and would have to wind motor over on starter till it cleared which usually wasn’t long and not a real drama.
Only drawback of such high-pressure cooling system was splitting of radiator top tanks and leaks around seams.
The top tanks on ‘R’ and ‘S’ Series Valiants were more prone to split than the improved top tank design on AP5 onwards.
The radiator cores on early Valiants were in my opinion superb and gave many, many years of service unlike our modern cars radiators which in most cases have very short life-spans, but must add are very cheap to replace in comparison… I purchased a new AU Falcon on line for only $105.