Ive been having a shake that affects the whole car. Basically I can feel it in the steering wheel and in the seat. It “feels” like it goes more into the seat sometimes and others it’s pretty balanced between everything. I’ve had my tires balanced a total of 5 times, the last 2 times they were road force balanced. I have noticed that the shake seems worse at around 14-1500rpm, but is still there at higher rpm, and when put in neutral coasting, although less of a shake, and the higher the rpm the less of a shake. So basically cruising in 5th at about 50 the rpm is around 14-1500 and it shakes throughout, drop through the gears and the rpm increases and the vibe seems less. I’m wondering about the flex jurid on the driveshaft, but it was replaced by one of the previous owners when the trans was replaced. Has anyone had this personally and resolved it? It’s more annoying than anything.

 

Could this possibly be caused by a failing prop shaft centre bearing (shake in seat) ?

 

I have yet to crawl under, but I thought the xk8's weren't supposed to have the center bearing. Hmmm of course seeing as how I just found out I have a pollen filter, it might not hurt to look! I had planned on crawling under it yesterday, but time got away from me

 

Hmmm, sorry, didnt realise the xk8 dont have the centre bearing..
One less thing to check when under the car..

 

Sorry to hear about this. I know what it feels like. I recently had some vibration, I was due for new tires though. Once I put the new tires on, balanced and aligned, the car rides very smooth at any speed. Are your tires on the older side? Or worn? Have they checked your alignment?


I also had this problem a few years back on my 05 XJR. It was the drive shaft for me. The rubber mount around the center bearing was destroyed.

If you don't have this component and your tires are good, the other thing I would check is your motor/trans mounts. Do you know if they have ever been replaced?
,

 

Tires are about a year old now and have been balanced several times including road force balance. I did have it 4 wheel aligned about 3mo ago so that should be ok, it was shaking before that. As for the mounts, Im fairly certain the trans mount was when the trans was replaced, but I don't think the engine mounts have been

 

From what you describe, it could be the front brake rotor disc/s out of balance. It's unusual but not unheard of.
Sometimes, when very hot, they can warp slightly and then wear unevenly - ultimately becoming imbalanced.

It would explain the symptoms you describe and seems to be the only rotational wheel element that you haven't checked.

However, I think you would feel some vibration when braking...

There is also a drive shaft coupler that can produce run-out and vibrate. I'v never experienced it but it's location at Trans exit may be significant.

 

Is this new or did it come with the car?

I was thinking possibly prop shaft:- the workshop manual stresses witness marking when disassembling the couplings so everything goes back together in the same relationship.

Does the jurid look OK?

 

I actually did have some vibration in the wheel when braking and thought the same about the front rotors. I bought and installed a brand new set of Beck Arnley front rotors and no more shake in the wheel at all while braking, however it made no real noticeable difference in the whole car shake. The shaking kinda came on gradually and I think at times, it feels as though it has progressively gotten slightly worse. To be fair, it's not "teeth rattling shaking" but it's still really annoying when I remember how smooth it was.

 

So you’ve sorted all wheel/axle related vibration sources and, by elimination, I’m thinking only the drive-line remains (as per michaelh comment).

At the Gearbox exit there is a flexible ‘Guibo’ coupling that connects to the prop-shaft. When this fails, splits or perishes, it causes run-out and vibration. It’s location next to the main gearbox mount will transfer vibration to the tunnel and explain the condition you describe.

I think you need to get this investigated / inspected. It’s not easy to see under the car but this is it’s approximate location...




There is a thread here on how to change it

https://www.jaguarforums.com/forum/x...x-disc-211000/

 

If you don't have a bent rim, or hidden mud in the rim,. May even be a lil rust between the rim and rotor causing not to run true. Sounds to me most likely a bad tire with a shifted belt. A bad tire can drive you nuts trying to figure out sometimes. Put about 55 psi + in each tire and do a slow test drive. If the vibration changes to a higher speed, there's your issue. The extra pressure will tighten up the belt somewhat and change the characteristics. Bleed pressure back to normal after short test. The rear axles can cause a vibration. Check for tears in the boots. Otherwise, an ignition coil could be getting wet. Loosing coolant? Rain? Engine check light on? The cork gasket on the coil covers can allow moisture in the plug wells and cause a missfire. I put petroleum jelly, (vaseline) on my corks and plug wires. Haven't had a missfire in 10 years.