This only happens when the car hasn't been driven overnight and I start the engine in the morning. When I start the engine, a few seconds or minute or two later, I hear this hard to describe sound: it kinda sounds like clicking or raindrops falling on a metal roof. It continues off/on until the engine is semi-warm. I opened the hood and I don't see or hear anything. I just hear it inside the cabin and it disappears after the engine is warm or at normal operating temperature.

 

Another way for me to describe the sounds: if you have a sheet of aluminum foil and you shake it gently to makes waves with it, you can hear some crispy but faint metallic sounds. :-)

 

Turn off the climate control and see if the noise stays there.

 

Yeah, along with what Fraser asked, I was gonna say it's probly the cabin pressure...

 

actually, the climate control is off. But thanks for the suggestion. Any other ideas?

 

Possibly noisy lifters?

more info here:

MotorEx - How to Fix Noisy Tappets/Lifters

 

Thanks Meirion1 though I think I kinda know what a noisy hydraulic lifter sounds like. This one sounds like if you take a 12-18 inch long sheet of Reynolds aluminum foil out and wave the sheet, it will make some kind of sound, that's what the sound is what I am hearing, not really a ticking or pinging hydraulic valve lifter.

 

If you are starting the vehicle in an enclosed area, you may be hearing the exhaust system expanding as it warms.

Unless the sound has a consistent rhythm, say from the timing chain tensioners lacking sufficient oil pressure, it may just be the sound of metal expanding.

 

Thank you NBCat. Regarding your first comment, my car is parked in an underground enclosed garage and I never heard that sound before and I've lived there almost a year. At first I thought what you thought that it was just metal expanding but I think it's more than that. Can you please explain what timing chain tensioners lacking sufficient oil pressure involves? I mean is the oil pump going out or the timing chain tensioner is loose or ??? Any feedback would be appreciated. I will record the sound and post it on here if I don't bring it to an Independent Jaguar dealer first.I'm just thinking they mechanic won't hear it unless it stays at his shop overnight.

 

Very unlikely to be tensioners on this engine, possibly vvt solenoid.

I suggest you search this forum for vvt solenoid noise ( I use

google).

I found this:

https://www.jaguarforums.com/forum/x...sioners-71904/

 

I tend to agree that it sounds much like metal heating/expanding maybe a heatshield or cat/exhaust components.
Try closing the manual cabin cold airvents and see if it goes away?

 

Many AJ-V8 engines have a slight 'rattle' on being started following a cold soak that can be caused by the timing chains. This was more common in the AJ28 and other early versions of the engine until Jaguar addressed the situation with a revision to the design.