I am in the UK and we dont have much in the way of spares so ......

I needed to replace my radiator and overflow tank.

The radiator i aquired does not have a cap for filling just a small outlet for overflow.

So I have added a header tank with pressure gap from a VW Golf which has a small hose that connects to the radiator small hose.

The other 2 normal radiator hoses are standard but i still needed to get wather into the system so I 't'd the hose from the bottom of the VW Golf header tank into one of the heater hoses.

Now I filled the system fine with no problems.

But what happens is when the engine is running the coolant tank fills right up ( I guess with the water expanding when hot?) and then looks almost empty when not running.

Anyone got any ideas if this is ok and why it happens?
Or does anyone know this is a bad idea and I need to change it?





Also I have this leak on the inlet manifold -
Any ideas - is it coming up the thread?

 

You need a cap to pressurize the system, and you need somewhere to catch the overflow from that cap.

 

It does have a pressure cap - it's blue in the picture .
The system does pressurise.
Just dust expect such a level change ???

 

The overflow pipe from the cap goes to the top of the rad.

 

What's the pressure rating on the cap?

 

Not sure ill try to check tomorrow and report back .

 

No marking on the cap