It seems I have been a bit silly and put my header tank too low so here are some pics, I would really appreciate any advice as I want the car on the road this year and I need to get to iva ASAP. It seems a major oversight in my part, but all I can do now is try to re-engineer again!!
Ok so with the marlin space is limited for the radiator, this meant I had to go for a tall and thinner rad. I used the Honda Civic alloy one from eBay. As you can see below I have had to do a really horrible bend to get the outlet of the thermostat up to the top of the rad
This gives the problem of the rad inlet being pretty much the highest thing in the engine bay.
The header tank is shown below
So looking at it now the outlet of the header tank is sitting around 6-8 inches lower than the rad top hose. This is giving the problem that when the header tank is half full there is no water in the top hose/ top of the radiator.
I have to pretty much brim the header tank to get atleast some water in the top of the rad. Which defeats the point of the header tank.
So thinking of my options, I either have to change the radiator and try find a more rectangular one with an inlet that sits at least level with the thermostat outlet. Without going custom I think this will be difficult as I spent weeks looking for something that would fit when originally fitting the rad.
The other option is to use a different header tank possibly a funky shaped plastic one that I can sit higher in the engine bay, the problem is that I have very little room with the bonnet, it would have to be rectangular and thin, width isn't really an issue though. I cannot lower the current rad at all so That is not an option
So open forum, any advice welcomed. And a beer to the first person to call me a twat for overlooking such a simple thing!!