Just thought I'd ask all of you much more experienced XK8 owners about a characteristic of this engine that to me is some what unusual. When warming up and after engine shut down it goes snap, crackel and pop much more than any engine I have ever owned. And one of the pops is pretty loud. You can hear these noises with the hood closed. Inside the car it is not noticeable. But if you listen you can hear them there two. About ten seconds after starting and some minor snaps there is one pretty loud pop that seems to come from the center of the engine right under the black air induction tubes between the cam covers. Same thing about 30 seconds after shutting the engine off.

Am I concerned about nothing? Probably am. Until I get to really know a car I carefully observe everything. Guess I picked that up during my flight test engneering times. It is a curse.

Let me know what you think.

EZDriver 2000 XK8 1995 XJ6

 

I would consider this normal. My 99 coupe does that. Wait until the summer heat hits then you will really hear some popping. If you look where the cats are compaired to other cars these are contained under the hood perpendicular to the ground. When you hear them popping you can open the hood and listen to the symphony.

 

I, too, have noticed the sonorous symphony coming from under my recently purchased '03 XK8 after a drive - didn't think much of it as I have noticed this from many modern cars that run fairly high underhood temperatures. All the car's drivetrain components will tend to heat and cool at different rates, causing the popsandcrackles. Short of any explosions, probably no need to worry.
Cheers,

 

Most of the popping and cracking from the 4.0L engine stems from all the stainless heatshields. One big one runs the length of each exhaust manifold, seen below the cam covers; actually, those ARE the manifold gaskets. There is also a jigsaw puzzle of shields at the top of the LH catalyst, protecting the coolant tank and the heater pump, valve and hoses.

It's the 4.0L symphony!

 

my 97 does it, always has, don't worry about it.

 

Thanks guys. That was good info. I didn't think about all the heat shields. That makes sense now. 4.0 music huh???