For what it's worth, I seem to be tracking the (near?) same problem here:

https://www.jaguarforums.com/forum/x...-member-87491/

23 year experienced Jag tech/shop owner seems to think symptoms point to one cylinder not firing - or at least firing at wrong time.

Will know more in a few days.

 

Thank You! That is forcing me about the slower than normal flame expansion (after ignition) in one, or more cylinders, until the engine gets a little warm.... and the piston, -s is/are knocking in the cyl..

 

Hello from Poland.
I'm getting exactly the same sound in my 4.0 X308. Knocking when engine cold, louder on D or R, when engine gets hot - knocking gets totally away. The engine always runs perfect. Driving with this from about 8000 km.

My question is - how is your knocking now?
Are you still driving with it?
Still the same/worse? Have you diagnosed or repaired it?

 

Still the same 15k miles later

 

About the same, as earlier. New, that I hear it when the engine is warm sometimes, but quietly.
I got even an XKR since then, and it has the same sound after cold start up. This car ran only 38000 miles.

 

Thank you for your answers, now I can sleep peacefully
And as I can see, there is no need to look for the source of knocking and disassemble the engine, at least until they are not heared all the time (on hot engine) and the engine runs as it should

 

Turn up the radio!

 

I did that, to drown out my funny noise. Now the subwoofer has blown, and I'm fixing that. Still, it's easier than an engine teardown.

 

I had the same problem with engine tick/knock when cold only. It sounded like sharpening a French chef knife with a knife sharpener file. I thought my supercharger was being destroyed.

I eventually found the cause which was a split in the stainless steel metal tube from the exhaust manifold to the EGR valve. The split is hard to spot and is in the corrugated section of the tube. I only found the split when the engine was running and I saw the insulation of the EGR valve tube flapping rhythmically. I replace that tube and problem solved permanently. It's been a year now, no sound and runs perfect.

I thought I had the wrong oil filter (incorrect), need to change the supercharger oil (incorrect), use better quality engine oil (incorrect) which I did, but to no avail. Replacing the EGR valve tube solved the problem!

 

Heh, heh. That one could be classified as a certified PITA to find!

 

Thats interesting, as I have a strange noise, AND an EGR code!

 

BTW, did you get any codes when you had the split in the pipe?

 

I was very happy reading it, but then I've realised, that... I don't have EGR, because I have 4.0 Sovereign, not XJR..
Or maybe X308 4.0 without supercharger also has an EGR?

Anyway my engine knock is EXACTLY the same as on Markocosic's video.

 

I just checked the Jaguar Technical Guide - AJ-V8 Engine and 5HP24 Transmission Introduction book, page 37 on the EGR system it clearly shows a picture of the stainless steel EGR tube which they call the "transfer pipe" connecting from the right (passenger) exhaust manifold to the EGR valve. That transfer pipe was what had the split and was replaced. It costed around $200 dollars and five minutes to replace. The picture shows a non-supercharged engine. See attached PDF.

 

Thanks, XJR Pilot! I'm gonna check the EGR (if I will find it!) and that transfer pipe. Hope that this is the problem

 

No codes show up. That was the strange thing....

 

So, does an AJ27 NA engine have a EGR valve?

 

JEPC shows one from VIN A00083 on the XK8, but I don't know what engine that is for sure. Also XJ8 from VIN 812317.

 

Unfortunately, my late 2000 XJ 4.0 hasn't got EGR valve..

 

I don't think any NA XJ8s do. The VVT allows the valve overlap to be used to perform the same function.