Im hearing loud tapping form the top of the valve cover people say its normal but i dont think it is by any means. Its not regular valve tapping. its alot louder. Makes it sound kinda like a diesel.

 

what year?

 

1990 xj6 4.0

 

it could be a timing chain if you can't pinpoint the exact side where the noise is.

Here's a Low Tech way to try to pinpoint the noise: start the engine, get a long piece of wood, (a broom stick without the broom works well), place one end overa valve cover, the other end to your ear, this will transmit the noise to your ear without any risk of damaging your ear drum. Do it on each valve cover.
Keep your hands away from the BELTS, FAN,and ANY MOVING PULLEYS.

 

1badjag.........have you checked? Maybe it is a diesel....
Sorry bro, couldn't resist

Jim

 

Does it get wore as you rev the engine? There is a replaceable timing tensioner on the right side of the engine. Easy job if it's the cause.

 

it dosent get worse..... it just tapps faster along with the rpms

 

LMAO!!!! Yes ken, it gets worse as you rev the engine!

 

Behind the distributor (yes, XJ the distributor again) you will see a plate with two bolts that lines up with the timing chains. Check to see if this is where your noise comes from. Jaguar updated this tensioner. Send a PM about parts, etc.