Hi please can someone help I have a Mazda5 2.0 petrol it had a persistent knock coming from the engine I checked the oil and it was below the minimum line so I done and oil and filter changed on it and its made the knock even worse I've tried bleeding the hydraulic lifters but still knocks I then removed the auxiliary belt and still knocks it sounds low and to the left I've attached a MP3 of the sound can anyone please help

Regards
Dave