Radiator water levels

[peterg]

I looked into my radiator today and the water was level to the bottom of a plate that runs diagonally across inside the top of the radiator, just above the cooling fins.
I'm more used to sealed systems. Is that the correct level for a Bristol radiator?

On a brighter note I managed to seal all the joints, primed the fuel pump and get the engine running today!

[flyinghorse1]

My system is empty at present whilst I fit a new water pump so cant tell you whats normal ,but it does seem low from memory.
Have you checked the radiator cap? The system ought to run at a low pressure with any cooling medium expansion being lost out the relief in the radiator neck.

If you have no pressure rating on the cap/its weak old or leaking you will loose the full expansion of fluid from cold to hot and that may be giving you the level you see. A cap that holds a bit of pressure (4psi) will loose less water on a expansion cycle.
Also need to be running some antifreeze mix (I run 50/50).

I also like to see clear water/antifreeze draining from the small water tap on the block .

I took of each end plate and flushed my block through. If you take a stainless steel rod from a wiper blade in a drill to can clean the passages out well.

What temperature is the car running at as I guess this is the real issue? If its very hot you may need to check its not running retarded. I assume you have a cooling fan? Does it have a thermostat or is it one of the types that don't have one? Do you have a heater circuit?

[Ronald G. Stephenson]

All old cars need room at the top of the radiator tank for expansion. With pressure caps of 4 to 7 pounds, they only amount to a pressure release valve. To be sure, it is important to have water/anti freeze in your overflow bottle, with the hose below the water level. Ok, engine heats up, water expands, and that space in the top of the radiator gets filled up. If it gets hotter, the water has to go somewhere, and it is important to fit an overflow bottle. Upon cooling down, the water will be drawn back into the radiator. Years ago, I was shown by an experienced mechanic to just cover the 'fins' in the radiator, and never 'fill it up'. Very easy to construct an overflow tank or bottle if you do not have one, and it can be easily hidden from view. Do NOT fit a higher pressure cap unless you want more leaks than you can imagine from every fitting on the engine.