While driving a noticed this very low sound, at 1300RPM, like a resonance or sth, speed does not matter - only the motor's speed. It is somehow worrying me. I do not think it is the exhaust system. Gear box breaking? Hopefully not.

EDIT: Ah, I managed to find information about this, it is a known problem. I wonder if Jaguar still sells those extra mounts or has somebody done it DIY-way?

My car is an early -07 XK Coupe, driven only 55 000km.

 

This bothersome noise on the early model is very well known and Jaguar provided an effective fix for it. It is not a mechanical noise, but a resonance which begins at about 1250 rpm - right in the "normal" driving range. It is not dangerous in any way and does not indicate any mechanical malfunction.
The fix is a bracket fitted between the exhaust system and the transmission case. It ends this nuisance instantly - and I say that from my experience with my own 07 coupe. The bracket and its installation is not cheap but it is 100% effective, and permanent. It transforms the driving experience of these gorgeous cars. If you pm me I can give you the part number. Your dealer with have a service bulletin on this issue.

 

Hi Sov, I have this issue and it's never really bothered me once I knew what it was. I would fix it if not too expensive. Is it doable as a DIY.

Would you be able to post the PN.
Thanks

Trevor

 

Everybody says it is "an expensive fix by Jaguar" but nobody says how expensive. So...?

 

If cost is a concern and you're a Do-It-Yourself person, you should be able to fabricate an effective bracket using inexpensive generic exhaust hanger parts, including straps and rubber insulators, available in different styles and sizes from your local auto parts store.

 

I think I still have mine from pulling the stock exhaust off. Two straps with brackets in the middle of the picture. They weren't difficult to remove and use transmission bell housing bolts to hold them to the engine. They were still in decent shape but will need new clamp bolts as they were buggered.



I'll need to rummage around the junk pile to see if they are still at the shop.

 

I am interested to buy them if they look ok! I send you a pm, ok?

 

It is not inexpensive, but it definitely cures the noise. There are two brackets mounted between the left and right exhausts and fixed to the transmission case. The price of the brackets, left and right, were $350 Canadian each, plus installation. The absence of the resonance transforms the driving experience. I don't have the numbers at hand but I can post them later. Ah...here they are: C2P13477 and 13478.

Gregory

 

Jaguar Parts International has these brackets at $221 usd each

 

There is a thread on this forum where a member posted a drawing of the brackets with measurements for the DIY'er to make their own. A search on the part number will probably find it.

 

Good because I was unable to find my old ones last night. I guess they are headed to the shredder.

 

Sigh...ok.

I can't put them in myself, and I do not know if somebody would install the ones I made myself. They cost about 600 US dollars here, and if I order from the States, there will be tax and VAT added to 221 x2 = same price, or more :/

Originals installed = 950 US dollars here. Hm.

 

That is not much more than this cost me 6 years ago; since the noise bothers you, do it if you can afford it. It makes an enormous difference.

 

I never understood that the cure was so effective. Do you know when was that incorporated in production ? So far the huge difference I experienced was between the 4.2 and the 5.0 variants, not between different 4.2 models. I find the 5.0 engine (both in n/a and sc variants) much smoother and completely free from any resonance or vibration, didn't get the same feeling in the various 4.2 models I drove.

 

There is no resonance and no vibration in my 07 4.2 car - just a smooth flow of power. Having the brackets installed was worth every penny. The complaint about the resonance seems confined to the cars manufactured in 06 and 07, so perhaps for the 08 model year there was a slight redesign of the exhaust?

 

I found mine, laying under the hydraulic press in my garage. One of the bolt hole tabs was broken and may show up today as I do a spring cleaning on the shop.

 

AHA!!! So that is what it is! I was just getting ready to start a thread on this. Mine is an 09 and I get this rumble, not quite like driving over a rumble strip, but close, at 1250ish rpms and was worried. Now, not so worried. My husband builds hot rods, so I am sure if I can find the plans as mentioned above he can fabricate and install for me. Awesome!

 

Mine is an earlier model...from 1998, but still doing the noise when I drive between 120-135 kmh...:-(

 

Then don't drive between 120-135 kmh. Solved!
Or, yours may be some type of undercarriage panel vibration if it's speed-dependent.