Can anyone tell me what this pipe is called. As you can tell I am new to this

Is this a mk3? If so you're better off posting there.

But looks to be a coolant pipe coming off the bottom of your radiator 

It looks like an intercooler hose, if that helps. 

Edit :Or based on the above I could be talking nonsense.

 

Edited 9 October, 20178 yr by Bogwoppit

What engine?  Is it a 2.0 FSI?  If so, it's the lower coolant hose.

 

If it's a 1.8 or 2.0 turbo then it's the intercooler  to inlet manifold pipe.

Thanks to all you people for your help. My car is a mk2 Octavia 2.0tdi and the hose looks like there is oil or something leaking from it

Edited 10 October, 20178 yr by boffyb

Normally the part number is printed somewhere at the part...

 

Example : 1K0 145 838 N    is the partnumber ( NOT YOURS, only example !!)

 

I'm pretty sure there's an O-ring in there

Pretty sure that's going to be the lower intercooler pipe.

Intercooler pipework if it's seeping black oil.

 

Otherwise if it's the same colour as your engine coolant it's for the radiator.

 

Re intercooler:

 

Pull the ring clips, remove the section of hose, clean and inspect the fittings for abrasion wear and replace o-rings if required.

Thanks for your help people

That diameter is always intercooler connection

http://workshop-manuals.com/volkswagen/golf-mk6/power_unit/4-cylinder_diesel_engine_(2.0_l_engine_common_rail)/exhaust_turbocharger_g-charger/charge_air_system/assembly_overview_charge-air_hose_connections/assembly_overview_charge-air_hose_connections_with_connector_couplings/

 

What enine code (3 or 4 leters) it is and year?