Coolant Leak - Radiator?

[giorgio1712]

The first problem with my GTI has occurred. The coolant/water whatever you want to call it is leaking from somewhere. This is causing the red light on the dash to flash and the needle to creep up to 3/4 after about 10 minutes. I think it may be due to this red hose going from the top corner of the rad to the top of the reservoir. I presume this is for steam/water droplets to return to the reservoir or am I just stupid? Its the small hose in between the two big ones in the picture below.



Heres a video of the steaming.....




After a journey steam starts coming out of what looks like the connection between the said hose and the rad so will it just be that this  needs tightening up or will I need a new one. If so does anyone know the part number?

Cheers

[Diamond Hell]

That's a small plastic housing that the small pipe goes on.

After 15-20 years it may have become brittle and then fractured.  Now your car cannot pressurise the cooling system and run the higher temperature a pressurised system will run.  Where this hose is should be below the 'water line'.

I think you're going to wind up replacing the radiator, as I think that barb is knackered.

You need to have that pipe off (when the coolant is cold) to start having a look to see what's what.