Jaguar Repair Problems? Ask a Jaguar Repairs Expert.
Sounds like the noise may be coming from the variable valve timing units. First make sure the oil is clean and full. Then before starting the engine go under the hood and put your hands on both of the VVT solenoids. Have an assistant start the engine and see if you can see which one is noisy. Let me know.
The noise is the actual vvt which is the intake cam. The noise travels up through the solenoids. The actual vvt will need to be replaced.
Unfortunately you can only get it from Jag. Here are some sources I use for discounted parts. Coventrywest.com, jagbits.com, welshent.com, and motorcarsltd.com.