82 xj6 series 3. When I open the hood at idle there is just this constant tick noise I don't know where its from. It doesn't effect the performance at all when driving. Any idea what it could be. I don't want to neglect it incase its something I should be worried.

 

Try and find an automotive stethoscope and listen closely to the engine.

 

Probably a valve adjustment issue. A slight tick is ok, but a loud clank is not. A valve lash check should be done at some point.

 

Could be a tappet guide has loosened and is knocking the underside of the camshaft. You need to listen to the cam cover with a mechanic's stethoscope, (a long screwdriver will do with your ear at one end, the blade at the other end pushed onto the outside of the cam cover)

 

If it stops ticking either cut the red wire, or run like hell.

Sorry, couldnt resist it.

 

The injectors make a heck of a racket on my car. Listen to them with a stethoscope. That may be what you are hearing.

 

if you or the previous owner have not installed the tappet guide fix, then that could also be what you are hearing.

My '84 always ticks a little when cold, then the ticking goes away as oil circulates.

 

I had a loud ticking noise that turned out to be a defective water pump.

You will need a stethoscope to hear it well, as others have said. You may also be able to test by seeing whether the fan can be 'jiggled' on the pump pulley, although I had a good loud noise without any apparent looseness.

 

The mechanics stethoscopes people are talking about can be bought for just a few $ , they are a very handy aid in locating the source of ugly noises.

 

Where can I get the tappet guide fix?

 

They are usually listed, on the websites of the usual Jag parts suppliers, as "stakedown kits". Take a look. I got mine from Coventry West.