2001 VW New Beetle - Timing Chain Tensioner

I have a 2001 New Beetle, 1.8L Turbo with 83k miles. It had a new timing belt (front of engine) and all related parts at 60k miles. Everything has been fine until recently when a metallic clatter has shown up. It does not clatter when the engine is cold or when it is running at speed, but if it is warm and idling, it clatters. The mechanic suggested the timing chain tensioner, but he replaced the oil pump to be sure that sufficient oil pressure was being delivered (it was low - the specs apparently call for a minimum of nearly 50psi). We are now going to replace the tensioner (chain between the camshafts on the back of the engine). If that fixes the problem, I’m ok - but what might be next? There are no unusual bearing noises or anything that would suggest a worn engine; the mechanic is replacing the tensioner for zero labor cost unless it fixes the problem (he’s very reputable). Ideas or suggestions PLEASE???

Was the tensioner replaced with the timing belt replacement? It along with the water pump should have been replaced.