Originally Posted by
DanW@FastFord
The MoT is no guarentee of roadworthyness! Worth getting them checked out as its a simple fix if it is one of them.
Get your head in the engine bay and have a good look around for anything wobbling. Look at the belt and make sure it's running 'true'. It was all swapped, but it's a Mk3 weak point.
Yer will have a look at the weekend, I know you did the bottom aux pulley and tensioner, but I know they do fail quite offen. Might be something silly like the plastic engine cover vibrating.