I have researched all the threads I can find and don't see a definitive answer . I checked for slack through the oil fill cap and there is about a 1/4 inch of slack before cold start. There seems to be a slight rattle when starting cold but hard to tell if it's the chains, high pressure fuel pump or secondary air injection. It seems to go away in a few seconds and after the idle comes down there is no rattle type noises. After running for 30 seconds or so and rechecking the chain , it is tight .. When starting hot all is quiet.. The car is a 2011 XK N/A with 75k on the clock. My question is for anybody who has monitored their chain wear and proceeded with a repair or have let it go until it really starts to make a racket. All opinions are welcome . Thanks all in advance

 

1/4" is too much slack, it should be tight, it is a ratcheting mechanism.

The startup noise can be caused by the VVT actuators getting clogged up with oil.
I suggest having at minimum the tensioners and guides replaced via front of engine.

 

It does sound like something which relies on oil pressure to eliminate slack and the cam chain tensioners are the obvious target and are a weak point on the 5.0 engine unless they have already been changed to the new design. The slack in the cam chain when cold is excessive and is the first sign of a failed tensioner. Take care because as the play increases the danger of a jumped tooth under acceleration increases.

Richard

 

you will get a death rattle and a p0016 when the tensioner pushes through

 

As I stated after starting the chain is tight and engine is quiet . When checking the tension again after letting run for 15 seconds or so there is no slack in the chain . I am more concerned with it jumping time upon cold start .

 

personally I would not drive the car with 1/4" slack on startup, regardless.

 

When I said "as the play increases" I meant as the tensioner develops further wear over months/miles of operation.

Richard

 

Understood