the dual mass and vvt can cause lots of rattle on these cars thats if the rattle is not from core of engine itself, I break 170s all the the time and most common causes are normally the dual mass and vvt, and this is normally main reason I break them when people see a bill for a dual mass and clutch kit for around £500 and the vvt pulley and solonoid £250+ thats parts only no labor, normally why these cars sell cheap on the 2nd hand market