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 S-Type Plastic Timing Chain Tensioners May Fail and Cause Engine Damage
Jaguar S-Type Problem
Model Year Affected: 2000
Engine Affected: 4.0L V8
Average Mileage: 80,065 mi (72,130 mi - 88,000 mi)
Visitor, 2000 Jaguar S-Type, 4.0L V8, 72,130 mi
made a strange noise while in park idling shhut motor off for 10 minutes tried to restart and no-go both tensioners broke during start up and chains stretched (I know how does metal stretch?) dealerships will rape and violate your ass, but they have the parts and tools to do the job. good luck.
Same. Lucky it didn't cause noticeable damage.