Hello fellow sufferers,

I have a weird issue with my X308 XJ8 4.0 with an AJ27.

Car has around 45.000mls on the clock.

Bought it recently, drove it around 150-200 miles.
No problem whatsoever.

When I had my appointment for the first oil change in my possession, I decided to change the viscosity of the oil from 5W30 to 5W40.
I decided so after thinking back an forth a lot and thought it would be reasonable because of the relatively hot summers in south west Germany.

Used Motul XCess 8100 5W40 with the correct specifications.

Anyway. First cold start after the oil change the next day: rattling after start up for a few seconds.
Rattle went, car was running fine.

Ordered a timing chain, guide and tensioner upgrade kit immediately. Wanted to do that anyway some time soon.

Next cold start a few days later: no rattling.

Next cold start: rattling again. Doh…!

What I observed is a very slight diesel-ish noise (so slight, I think most people wouldn’t even notice) when driving. The noise DISAPPEARS, when the engine is warmed up completely.

What’s a bit weird is the fact, that it appeared right after the oil change.

Just for verification: I suspect the VVT sprockets.

Or did someone experienced similar issues and it turned out to be something completely different?

Any opinions on this will be appreciated :-)

Cheers!

 

Can you be a bit more specific as to where the "rattling" is coming from?
Have you popped the bonnet to get a bit more familiar with the sound? The
only car I ever had that 'rattled' was a SS396 and that turned out to be a
heat valve in the exhaust system.

 

Couldn’t locate it yet. Will ask someone to start it with me standing next to the open engine bay soon.
Also tried to make a video once, but then it simply didn’t occur.

But I’ll keep trying to locate it.

 

Hi Chris & hello to the South West of Germany (Baden-Württemberg?),

Changing from 5W-30 to 5W-40 should be absolutely no issue - I definitely think that 5W-40 is better for me here in Australia (where it is really warm), and one of the reasons as to why I emigrated from Germany to Australia is that it was too cold in Germany - but you should be fine with 5W-40 anyhow. I use Castrol full synthetic (with the correct spec).

I hope you also swapped the oil filter...

When I bought my X308 (3.2L, no VVT) it also came with a rattle. I also thought it's the timing chain (& guides & tensioners), which I wanted to swap anyways, which is why I did not investigate in too much detail, WHERE the knocking is exactly coming from - I just talked myself into it being the timing chain, and I swapped it:

https://www.jaguarforums.com/forum/x...e-swap-266724/

After a successful swap, it kept on rattling each time after first start-up for about 10 sec.
Only then I took a "mechanic's stethoscope": Take a huge screwdriver, hold the metal end onto every bit of the running engine, where you think the rattle comes from and hold the grip onto your ear - that way you should find the source of the rattle...

That way I found the source of my rattle: The honey-comp-structure inside of one of the catalyst was utterly loose. I swapped both cats. All good now.

 

My 2001 XJR has this same piston slap noise at cold start for about the first minute or two and has for the last 50,000 miles since I bought it. I only heard it when I'm in gear and not in park or neutral, so I presume its only there when I put a load on it. I've been meaning to dig into the source for a couple years and just haven't. I suspect I may have a weak coil or something as a new set of plugs didn't resolve it.

 

Yesss, sir, Baden-Württemberg.

Yup, I also heard about that these rattling noises can also be caused by a shot catalyst.

I’m in the same situation as you were back then. Wanted to upgrade the chain drive anyway, but now there’s a little more urge behind all this.

However, I started to doubt that this noise is caused by the chains, guides or tensioners.

I believe if it would be one of those components checking out, it would rattle every time when started cold.

What’s weird to me is that (really rather quiet) tappet noise, which disappears completely when the engine is warmed up completely.

To be investigated further…

One or two minutes, phew…

With my car, it’s only a few seconds and then disappears.

After that I just hear a very slight noise that can only be heard inside the car and yes, mostly under load when driving. Which disappears eventually.

 

Just tried to record the noise again and guess what…
No pathologic noises. Like the last time I tried to record it.

I think the solution is to strap a smartphone into the engine bay permanently. Case closed 😂

 

If you want a little more info and piece of mind, I’d highly recommend pulling the lower oil pan, using a bright flashlight and a small mechanics mirror, look up inside the oil pickup screen and see if there’s any plastic timing chain guides blocking the screen. That can certainly cause oil pressure/volume loss which can also lead to a noisy engine. Obviously throughly check the oil pan for small plastic chunks. You can use an angled pick, compressed air and hemostats to remove any debris lodged into the screen.

 

Useful information there. Especially since I once observed that the oil pressure warning light took two seconds to go off on a warm start after the engine was running, which is a bit too long for my taste. Will definitely check.

 

The only reason I didn’t suggest removing the oil pickup from the block is that once you disturb that seal and you don’t have a new one ready to go on, it might not seal to the top of the pickup tube again and of course more issues. Thinking how old our cars are, every seal needs replaced.

 

Found a video where I caught it from the inside.

 

Maybe I'm going deaf, but I don't hear anything out of the ordinary

 

There’s a light rattle right after the engine starts.