Thread: Radiator expansion tank

Hi, what would be the benefit of such tank please

Originally Posted by sierrafery

Hi, what would be the benefit of such tank please

When you fill the radiator with coolant, as soon as the engine comes up to temperature it expands and this is relieved by discharge through the overflow pipe, on the neck of the filler cap, and if there is no provision to catch it, it ends up on the road.....!


But if we install an expansion tank, and connect the overflow pipe, then any coolant is caught in the tank. When the engine cools down, a vacuum is created and this has the effect of sucking the contents of the expansion tank, back into the radiator.

Thus the coolant is at optimum level at all times.

As regards the expansion tank, the overflow connection goes to the bottom and there is a further connection to the top. This serves as an air vent and an overflow should the expansion tank overfill, hence my query as to volume/capacity of such a tank.

Trust this goes some way to explain its purpose.

Norm.

Just acquire a RRC or similar overflow tank in brass, there'd only be half a million kicking around, to achieve the desired result.

The cap you put on such tank has to be right.

cheers, DL

hi fellahs,

completion at last, attached a few photos.

norm.

And the rest.

You also need a double sealed " recovery style " radiator cap for the coolant to be able to be drawn back into the radiator. A 600ml plastic coke bottle with a hose going down through the cap to the bottom of the bottle and a small breather hole drilled in the cap beside the hose does the job also.
Nice fab job Normbourne .
I see 350RRC already covered the cap ,,

Originally Posted by chopper

You also need a double sealed " recovery style " radiator cap for the coolant to be able to be drawn back into the radiator. A 600ml plastic coke bottle with a hose going down through the cap to the bottom of the bottle and a small breather hole drilled in the cap beside the hose does the job also.
Nice fab job Normbourne .

Hi chopper,

Thanks for the interest mate, yes I've installed the Recovery cap, the top connection which connects to the radiator tube, is extended inside the tank to the bottom.

Similarly, the overflow outlet at the bottom of the tank, is extended to the top of the tank.

There is also a breather in the top cap, but I don't know if that is really necessary.

Norm.

"Similarly, the overflow outlet at the bottom of the tank, is extended to the top of the tank."

Not sure what you've done here ?
I don't think you need that , so long as the cap breaths you'll be right.