Having totally failed to find a radiator overflow tank that will go nicely into my engine compartment I've decided to make my own - the type I
want isn't hard to make (the old-fashioned 'overflow from the rad cap when hot, suck in when cooling' type - not pressurised)
I plan to make a tank that can be fitted into a tight corner that would otherwise be wasted space, and free up the main area.
All I want to know is the volume I will need; can anyone estimate the capacity of the old Cortina overflow tank for me? Nothing too accurate - I
reckon 'near-enough' will do here! 
cheers,
David
The old Ford one perished and leaked. As long as there is some coolant in the bottom and the overflow pipe goes into it to siphon back as it cools it
only needs to be about a pint at most.
yours, Pete.
Cheers Pete,
That's roughly what I expected.
My search for a new tank has been very frustrating - the only ones I could find in the UK were the pressurised ones offered as replacements.
I found dozens in the USA, in all sorts of shapes, sizes and materias. Some were as little as $15, up to $100 for fancy chrome ones. Some of the
fancy ones were also available in the UK, at the usual $1 = £1 conversion rate 
- not that I need anything so gaudy or expensive. I got a lot of
useful ideas from the illustrations, though.
No - I'm going to make my own, which shouldn't be any problem - after all, if I can make a model engine boiler that holds a couple of
gallons of water at 90psi then I reckon I should be able to manage 1 pint of hot water at atmospheric pressure! 
cheers,
David
David if you still want to search, you could try looking into Toyota vans. The ones with the engine in the middle between driver and passenger.
My Space cruiser is the same and has a small expansion tank of about a pint. It is located below filler neck level in front left hand corner of
engine bay.
Terry
How about a bike drink bottle? Comes complete with nifty mounting bracket....
HTH Stu.
Will you lot stop confusing me with more choices!!!
Seriously though, I'm accompanying my son to the scrappies tomorrow while he dumps his tatty old Astra, so I'll ask while I'm there.
Syd - do all Sherpas have that tank, and all models?
Spyderman - I'll have a look for Toyota vans & Space Cruisers while I'm there.
cheers,
David
I thought the Sherpa ones were designed to be pressurized? Not a big problem to overcome, yuo would just have to make sure that the pipe from the
overflow is at the lowest point of the expansion tank, and put the pressurized cap on the rad, and the flat cap on the tank.
But there again, if you have room to fit one of these, it will work best pressurized.....
HTH Stu.
The bike drinks bottle works well. I used one for road and competition on my original xflow engine setup.
I bought a snazzy blue ali version with platic lid. I cut off the spout and drilled it through with a diameter just smaller than my overflow pipe. I
then had a tight push fit for the pipe. Drill the small vent hole out to 1mm and it's ready to sit in its nifty carrier.
Some say don't place it lower than engine or else it will siphon, but I never had any problems. The rad cap is designed to lift and vent excess
water then re-close, as the rad cools it will draw back coolant.
Oh by the way, it's important to cutoff the overflow pipe at 45 degrees and push it down in the bottle till it just touches the bottom.
Rob
quote:
To operate the way David wants, it will need to be pressurised, so flow will go both ways; from rad when hot, and to rad when cooling.
Correct - I will have to use an 'open to the atmosphere' overflow tank (as opposed to a pressurised header tank).
This was pretty standard on older UK cars, and still seems fairly common on some USA vehicles, if my google searches are anything to go by.
cheers,
David
David, you get the header tank to work in to work in pressurized form by swapping the radiator/header tank caps and a very minor rethink in plumbing....