water expansion tank leaking

[wadey]

Had a look in the engine bay of my 318ci this morn and notice a bit of a leak underneath the water expansion tank. looks like another trip back to the garage after just having a new air mass thingy fitted and a new belt. Before I take it back, can anyone give me any ideas what it could be?

Many Thanks..

[blackspider]

Quite common for the expansion tanks to crack on these.

Need to have the cooling system pressurised to prove where the leak is coming from

[wadey]

Thanks for that, header tank had split..