Hi, new to the forum, I have a '99 A4 b5 Avant TDI 167k miles.
Recently been loosing a lot of coolant. I've tracked it down to the plastic pipe between the top hose and the engine, it also houses what looks like the coolant temp sensor. Anybody know what this plastic pipe is called so I can get a replacement?

 

Hi, Ive got an R 98 TDI Auto estate with 129.000 on clock, It looks like your not the only one with this fault as my plastic has cracked also which caused me to nearly over heat into the red and nearly fry the head gasket. I noticed my coolant low last week and topped up so wether mine started to crack last week I don't know but it def cracked yesterday and its pretty bad now. Ive googled everywhere and its prob just a coolant flange. Audi dealer it is in the morning. Its a nightmare when you've just set off towing a caravan!!

 

If its the same kind of set up as American a4's than the part is called the coolant flange, if the tdi is different then I have no clue

 

£13 for the part, known as coolant flange. Also don't forget the gasket and seals that are needed for it. I told the bloke whoever invented in needs shooting as it could have cooked my cyl head!!

 

Thank you chaps, all ordered ready to fit at the weekend.