On this V8 engine, timing chain problems are very common. Because the timing chain tensioners were made from plastic, they can fail prematurely and cause serious engine damage. A noticeable engine noise while idling or during a cold start can indicate a timing chain tensioner problem. The engine noise may also be accompanied by a rough or uneven engine idle. Improved components are available to remedy this problem.Google+
Car Problem Reports
Jaguar XKR Plastic Timing Chain Tensioners May Fail and Cause Engine Damage
Jaguar XKR Problem
Model Year Affected: 2000
Visitor, 2000 Jaguar XKR, 58,000 mi
Timing tensioners have been O.K.however I keep the rpm's around 2500. Praying and keepimg my fingers crossed. I suppose the question is how did Jaguar get away with using plastic tensioners for 98-02 models. They should have issued replacement tensioners and participate in the cost. Most Jaguar owners would be happy with some kind of participation, oh well another corporate consumer rip off.