Expansion/header tank

[Howoodie]

Hi Guys

i have Chevy sbc installed in my GD. I have occasional cooling issues with air blockages

the highest point on the system is the pipe from the thermostat housing down to the header tank so the curve on the hose sometimes traps air I have a small breather vent but don’t want to worry about it and have too unscrew it etc

my engine builder has suggested I get made a bespoke expansion tank and run the heater hoses though this tank sited higher than the thermostat and discard the original low sited tank

any ideas or input would be greatly appreciated
Howard

[Happy Jim]

I take it you don’t have the GD header tank mounted on the chassis cross brace?

Can’t remember what it costs, but it definitely works

Rgds

Jim

[Howoodie]

I do have the GD tank but it’s much lower than the hose to the thermostat

[Howoodie]

Photo of engine bay
1551472A-6E57-479B-8C1A-50FC86E26596.jpeg

[KevinW]

that is a very tidy looking engine install.

[jon1d]

Your expansion tank is far to low. The pipe needs to be flat going into the tank and the top of expansion tank height above the thermostat housing. Raising the tank will elevate the air pocket issue. A 45 degree housing will give you the height .

[Howoodie]

Ok. So a new tank made and situated at the back of the engine bay therefore higher than the stat and run a hose straight from the stat to rad which will be much flatter if I use a different housing with a straight outlet. I assume I will still need a cap in this new tank fo4 pressure release and filling ?

[jon1d]

You need the cap as you say for filling and venting as it will be the highest point . Mount the expansion tank as close to the engine as.possible will give you more headroom between the filler cap and bonnet underside.. As an example the Fe427 expansion tanks are ontop of the engine thermostate housing thereby giving you a height mounting point.. Most builders have the problem of obtaining height . Another example is the Dax tank which is mounted in front of the bulk head and.slanted to give it height.

[superseven]

Hello Howard
If you can send me a PM, I can e-mail you some pictures. I have a GD with LS and recently changed by headertank. Bought a new one for approx 65GBP
Marcel