cinders

My cars in the garage at the moment getting a pulley for the air conditioning fitted... anyway the garage have rang me to tell me that underneath the car there's a hose that goes in to the intercooler from the crankcase or something and it's split and leaking air... the car is an MY98 UK Turbo...

I'm just wondering if anyone knows the proper name for this hose, and the part number by any chance? I'd like to order one from my local dealer...

Is it easy to replace? I'd rather do it myself than pay the garage money for doing it, I'm sick of paying out money to garages...

What will this split hose be doing to my engine?.. Will it be damaging it?..

Help?!...

Cinders.
(little worried)