There is a loud knocking noise coming from my 2009 Volvo XC70 3.2L AWD. The noise only occurs during acceleration. The knocking pauses for a split second when it switches gears. It seems it only knocks when the engine is under load. It occurs in both drive and reverse. It also occurs when the car is in drive/reverse and I give it throttle while applying the brake so it doesn't move. In neutral, the knock is less distinct.
Water pump has been replaced, idler and tensioner pulley replaced, serpentine belt replaced. Mechanic says engine mounts look fine.
Currently running 10w40 synthetic. Knocking becomes louder after car has warmed up. When cruising (not accelerating) the knocking disappears. The car has ~180,000km (112,000 miles).
I have attached a link to a video I took where you can hear the noise, sorry it is not very clear. Please ignore the low fuel light and warning light (unrelated).
Any ideas what this could be?
Thanks in advance