Sporadic 'tapping' noise until war.

[southernstar]

I have a 2000 2.7 986 with 55,000 miles (90,000 km.) and have noticed a sporadic tapping noise from the engine until it is fully warmed up. It does not 'rattle' on start-up and I can detect it from inside the car only when beside a wall that reflects the sound, as it is not very loud. If the car had mechanical lifters, I would suggest that it sounds very much like the tapping/clicking noise that was common with the earlier air cooled Porsches/VW's that were equipped with the same. It seems to disappear once the engine is warmed up.

I am assuming the problem is related to the chain tensioners; alternatively, I wondered whether one of the hydraulic lifters could be sticky? Either way, is this something which I need to address immediately? I have had the car for 3 months and have put 3000 trouble-free km. on the car and the situation does not seem to have worsened.

Thanks

Brad