Hi,

Bit of a strange one - would be grateful for any advice. I have an 08 XKR, but this is a general question about vibrations from the engine, so I'm using this forum. I originally thought I just had vibration through the steering wheel. I had the front wheels checked and balanced etc but it didn't help. I have now worked out that the vibration through the steering wheel is because my usual cruising speed has the revs at approximately 2200 and I have discovered (by holding the revs at that speed whilst in neutral) that there is a serious vibration through the whole car (including the steering wheel) at these revs. The same is also true at 1350 revs. Does this seem normal? Any ideas as to what the cause or solution might be? Thanks!

Roger

 

I dont know whether this will be of any assistance because we have an X-type, however we had a whole car vibration when getting upto and holding highway speed the thread is here https://www.jaguarforums.com/forum/x...bration-68742/

It may help may not but at least its a start.

Good luck

 

No, that is NOT normal, at all, if you feel vibrations when revving in neutral, assuming the car being parked. That is definitely some drivetrain (engine, transmission) vibration that should not be there.

In my '08 XK, I do have, what I call an exhaust-drone at both of those RPMs, but, they do not transfer to the steering wheel in the form of vibration. For the low RPM drone there is a factory fix but, I have to work on the 2000-2200 RPM drone on my own.

Albert

 

What catches my attention on this are the revs you reference. axr6 has pointed out a very common drone that occurs at the 1250-1350rpm range and is such a common problem on 07 and 08 XK's that there's a TSB on it. It eminates from a resonance in the exhaust/ catalytic converter. You either get the fix - which is a bunch of additional exhaust mounts or live with it. Could this get so violent that it would cause the whole car to vibrate - I doubt it but again it's strange that it occurs at exactly the same revs. Could be a drive shaft out of balance.

 

This sounds like an faulty engine mount...to vibrate the whole car requires a lot of energy.

I don't think the exhaust drone would be able to vibrate the whole car, and not come through the steering wheel.

I believe the XKR mounts are fluid filled? Perhaps one has leaked...

 

If they were still using the same mounts as the previous generation, its likely a mount. I had mine replaced by the dealer after only 3 years, its usually the driver side that rips (torque 'pulls' it upon acceleration than slams it back down when released). Many of my fellow x100 owners have documented it in our area of the forums (and more continue to show up)

 

Thanks for the replies everyone. Here's an update:

-First time I took it to the dealer, their Master Tech agreed it didn't seem right and investigated it. He concluded that it was the flywheel and it was replaced under warranty. The first time I tested in in Park it was much improved - gone at 1350 revs, and much reduced at 2200 revs.

Unfortunately, it has (after only a few miles) returned just as badly as before, so I took it back to the dealer.

The Master Tech (really nice, knowledgable guy) said he'd now concluded it's normal in that the engine can vibrate at certain frequencies when ut's not under load. He then got me to sit in two XKs they had in the garage. One was an XKR, same model as mine and it had exactly the same vibrations in Park as mine, if anything worse. He also put me in a non supercharged XK and that also had vibrations, albeit at different revs (which seems reasonable given the engine doesn't have a supercharger strapped to it).

So, does this mean it's normal? Well either it is OR the XKR I sat in also has a problem. The engine mounts sounds like an interesting route to investigate. Does anyone know how I can check whether the engine mounts used in the 08 X150 are the same as those used in the X100?

 

PS - I'm pretty certain it isn't connected to the exhaust drone. I have this at the lower revs, and it doesn't really bother me, but I don't have it at 2200 revs, which is where the vibration is at its worst.

 

To change the flywheel, you have to drop the transmission.

When it was put back together, it was gone. Then came back.

As if something "settled in".

Skidmark had a similar problem and it turned out to be .... the transmission mount. See discussion above.

 

Thanks Plums. Could it be the transmission mounts rather than the engine mounts? I was assuming it must be something in the engine because the vibration is there when in neutral or park, meaning the transmission isn't really doing much?

 

I have never felt a vibration in my XKR whether idling or driving.

The power train components of the car are designed/engineered and constructed to be balanced. A vibration severe enough to shake the whole car is not normal and would have to cause a reduced life of mechanical components. More over, as expensive as these cars are this would be inexcusable if it were "normal".

There has to be some issue with either a mechanical component in the drive train or the mounts (engine, transmission) used to isolate the drive train from the car. And even then, the engine and transmission should still be smooth in operation.

Jaguar refers to the transmission as "silky smooth" in operation...

 

Well, it wouldn't hurt to look

 

Thanks rscltho. I have no vibration at idle either. It's only in Park or Neutral when I gradually increase the revs to 1350 and then 2200 that I can really feel it. I also believe it is there when driving at these revs, but it's very difficult to tell because the car is moving. Any chance you (and others with 4.2 XKRs) could test your car in Park or Neutral? If most cars don't have it then I think I'm going to have to get an automotive engineer to try and work out what it is.

 

I have no abnormal vibrations in my 2008 XKR. I do have cold start vibrations, very normal on Jaguar and many cars, after RPM drops to 750-800 (about 1 minute) all normal. I do have the exhaust note drone at around 1200 RPM and under load, this became more louder after installing my Mina cat back exhaust. I like it! The mounts are hydraulic and when they fail it is very evident.

 

...more louder...? sorry about that!

 

I drove my car today...tested this in park, neutral, and during drive at the referenced revs. I tried and had my wife on notice too, but could not feel any vibrations.

I have 23,467 miles on the OD...

 

Thanks rscultho. You're a star. Mine has 19000 on the OD, so they sound like equivalent cars. Anyone else have a chance to test this out?

 

Rodger,
Just ran my '07 XK no vibrations at any rpm.
I think you need to ask Dealer to let you look at old flywheel! as a retired engineer I think changing it is a bit bazaar. Automatic flywheels don't fail!
V8's are not naturally in balance as opposed to 6's, however, they are not that bad and the flywheel is normally in balance, just a disc and starter teeth.
I find it hard to believe that Jag would pay for a different flywheel!
Since the problem disappeared for a while tells me to look at the mount system (eng & tranny) or the crankshaft front harmonic balancer (it may be a 2 part rubber/metal device) and they do fail but usually old age!
I can't explain the other jags on the lot; unheard off to me.
Keep trying.....

Cheers, Adrian

 

Thanks Adrian. Really appreciate the help. I've approached an automotive engineer about getting an inspection and report prepared. I'll post the conclusions in due course, but it would be great to hear from anyone else who can test this. The more people confirm they don't have it, the stronger the conclusion that it isn't normal/acceptable (or vice versa!)

 

Your welcome; rest assured it is NOT NORMAL!!!
If you can find a UK official Jaguar Cars Tech Rep (we don't seem to have one in the US!) you need to get his/her help..........
Don't give up!! Jaguars are always super smooth...................
I was born in Walton- on -Thames! Even my SS100 engine was smooth; not the ride.
Cheers, TTFN! Adrian