Here I am still shaking down my recently acquired 04 xj8. The motor seems very smooth at all ram's and has plenty of power. It starts up quickly, but sometimes, when cold or having sat for a while, there is a brief rattle from the motor compartment. Could this be the timing chain or tensioner? I've seen a few posts about this, but the sounds 8n the videos are different than mine. Any thoughts are appreciated! If it is the chain tensioner, does anyone know how much in parts and labor I should expect to pay to replace them?
(04 xj8, 4.2l 182,000 miles)

 

The rattling doesn't sound like metal on metal, and I just heard it when I started the car after a long drive, when the motor was warm.

 

Mine has done that very occasionally probably due

to a lifter where the oil has drained out and it disappears

immediately the engine starts because oil has filled the lifter again.

 

If you haven't done so already, the first thing that I would do is to give the car an oil change.

 

Hi Luke
I have also heard this, on my Super V8 and had the same concerns about chain tensioners etc. I did read somewhere that the noise on higher mileage cars is from the variable valve timing actuators. My car has close to 200,000 Km, but in almost every area runs perfectly, and gets 30 miles per (imperial) gallon on a trip. I don't think the engine has hydraulic lifters, but shims, but I could be wrong. My V12 has shims.

Pete M

 

I think Perte M is right, it is the variable valve timer filling up with oil. Until this happens the mechanism is undamped.

 

+1 on Fraser and Pete M.

Mine has had a few seconds of 'Death Rattle' every time I start it cold (if I switch off when warm and then restart, nothing) for the 3 1/2 years I have owned it!
My understanding (such as it is) is that oil pressure bleeds away from my VVT overnight and then (oil-starved) it rattles rattles for a few seconds as it tries to pin itself and the noise very quickly disappears when sufficient oil pressure has built up for it to do so?

I have learned to live with it!

 

As far as I know, there is a sprung lock pin in there somewhere specially to stop the 'death rattle', that is released when the oil pressure builds up, but over time it appears to fail if the car is left for some time.