V8 trike coolant hoses

[V8triketheworld1]

Hi all, Wonder if anyone could help? I have a custom trike with a 3.5 rover sd1 engine fitted. I've currently drained all of the coolant out so I could replace my thermostat and all the hoses that had seen better days, question is my trike is fitted with a rear mounted radiator with no cap and fill plug (looks to be an early Jag radiator)and instead a expansion tank with pressure cap mounted at the highest point at the front, can the whole system be refilled by this? I want to refill it now after all the work has been carried out but have noticed the only bleed point I can see is the hose in the centre of the twin su carbs manifold tower, but this hose is tied to the frame and is about half a metre long with a twist bleed screw in the end and that's it . Should this be returning into the top of my expansion tank? Currently the only inlet in the expansion tank is at the bottom which goes back to the radiator to an inlet just above the radiators top hose? My trike doesn't have a heater either so the water outlet at the rear of the inlet manifold is just looped, any help would be great, cheers

[Ian Anderson]

Fill it from the highest point

Then crack a couple of hoses at highest points to evacuate ant bubbles.

Start it and bring up to temperature….. refill header as needed

Well that is what I would do

Ian

[V8triketheworld1]

Cheers Ian, that's what I was thinking, I don't think the system it has on there is optimal, especially when it comes to refilling but considering it was first built like this in 1999 it's obviously worked well for a while

[stevieturbo]

If there isn't one already, it would be a good idea to add a header tank to the system, at a natural high point for filling, and to help reduce air locks in the system.

Equally, any point in the system that could trap air, run a bleed line from this to that header tank or other similar route where the air pocket can be evacuated in normal operation.

[V8triketheworld1]

Hi mate thanks for the info, I believe in actual fact what I referred to on mine as the expansion tank is in fact a header tank (my bad) , as I say this is only connected from the very bottom all the way back to the very top of the radiator in a small port above the top hose. The only bleed point I can see is the one between the twin su carbs in the inlet manifold carb tower and that is just a small length of hose with a manual bleed in the end (as pictured), would this work to lose the bleed valve and instead run that hose into a tee so it goes into the bottom of the header tank aswell, or maybe a separate hose into the top of the header tank? Cheers

[stevieturbo]

manual bleeds are ok, and many cars do run setups like that

But if it is convenient to run an auto bleed setup where the small hose routes back to the header tank, then I'd prefer that.

Obviously if that meant a long hose from front of the vehicle to rear, or visa versa, maybe that isn't always the best option, well not most practical anyway.

And header or expansion, I'd class both the same. Both to me would be a sealed tank which is part of the pressurised system. Anything outside of that I'd class as an overflow tank, as many cars run, and a hose in this from the pressure cap neck ( where applicable ), would push water into, and can also then draw it back in during cool down. This requires a 2-way cap setup.

But a header or expansion, is simply space in the system where you have an airspace to allow for expansion when the water gets hotter, so the excess has somewhere to go, without getting chucked out.