I wouldn't expect a main to sound like that. I have head bad mains and rod bearings and they sound nothing close to that.
Also, because it is not constant (pauses between ticks), it makes me think it is something else, but I am no mechanic.....
Let us know what you find out.
Tim (apparently likes "3" cars)
E90 M3 -- Current ride
2004 GT3 -- Sold
1997 M3/4 -- Sold
1995 M3 -- Sold