weve had our sedici diesel now for three months.until this week its run silky smooth with a really quiet engine.its now developed a really loud ticking noise which increases with engine noise.it still seems to drive ok but is getting really noisy.it has the sound the tappets need doing but i think there hydraulic.it was serviced when we got it.got it booked in on tuesday but any advice would be appreciated.its on 56000 miles.

regards pip

Hi, hydraulic tappets can get blocked sometimes, so the oil in them slowly get pushed out,and not replaced, increasing the gap, hence the increase in noise. Normally the only thing to do is have the tappet replaced, though you could try a engine cleaner ( works sometimes). The biggest cause is not changing the oil often enough ( short trips are the worst) and things get gummed up.