mine ticks from the front bank aswel, ive done every headgasket check known to man, it doesnt use a drop of water, a tiny bit of oil, and its done it for the last 10k miles, in which time its had some greif, so i know mine is my front EMG

as for yours. i dont know mate. id drop all the water out of it, remove all the pipes, check to see if any or blocked, or if there is a bit of impellar stuck, then flush it out, and see where your at then.