Many thanks to all who replied with helpful suggestions. Maybe it's now time to make a confession. In the 15 years I have had this car, I have always religiously checked oil, water etc before every journey. Just for once I didn't, and on a rather hot day after about 25 miles brisk(ish) driving I fancied that the running oil pressure was a bit lower than normal (4 versus 6 PSI). After getting home and parking up to open the garage with the engine idling, steam started issuing forth from various places accompanied by furious kettling noises. It took 2 or 3 pints of hot water slowly introduced before the normal level was restored. In all my years of motoring I thought that boiling up was a bit of a joke, and something that only happened to other people ! Shame on me.

Location: New Forest

Trouble really begins when all the water has gone. Many cast iron sv and ohv engines are remarkably tolerant. Unlike alloy ohc jobs.
Vigorous boiling was an accepted part of motoring years ago. To the 50s water stations were provided on one of our more severe routes. (Napier- Taupo)
My Seven had a tiny hole in the cap so any boiling was evident. When a sharp stop was acheived a tiny geyser of brown water shot over the roof. Large quantity must exit the overflow.

Location: Auckland, NZ

Bob - Apart from over-stating the obvious, what relevance has all that with the original question which has already been answered?
Thanks for wasting our time yet again. Cheers, Bill

Location: Euroa, Australia

Reading these posts is not compulsory, the only person who can waste your time here is you.

The problem is Duncan that it is not always apparent that a posting is deliberately wasting our time until you get to the end and realise it.
Those of us who see it coming deliberately avoid.

Location: Bristol

Seems like we will need to obtain prior clearance before posting on these
pages in case we are accused of time wasting.

Not a very friendly attitude.

Tommy. Melb. OZ.

The problem is Tom that longtime and valued contributors to this forum tire of the constant negative, miss leading, uninformative, and racist commentary from some quarters. Eventually they get fed up with it and speak out, only to be lambasted for doing so, other's go away and no longer contribute, as a result the forum is a poorer place. As the say one bad apple.

Location: Auckland NZ

Amen

Location: The Centre of the Universe