I have an XJ6 2.7 litre diesel - year 2008. There is a really bad vibration which I have been unable to identify. The characteristics of it are strange - see below :-
1 There is no problem at slow speeds e.g. 30mph - never. Because most of my driving is in built up areas, it could therefore very well be that the problem had been there for some time - just unnoticed.
2 There is no problem when the engine is cold - or at least for the first few miles of a journey - irrespective of speed.
3 However, if the car is driven at (say) 50 mph or above, after (say) the first 6 to 10 miles of any journey, there is a really bad vibration, felt mainly via the steering wheel, which rapidly turns a fraction of an inch to the right and then to the left. It would not be exaggerating to describe the experience as "scary". It is not pleasant to hold the steering wheel, because of the vibration (but of course you have to).
4 If you select 'neutral' with the transmission lever, whilst this is happening, (hence disconnecting the engine from the drive train) it does not make any difference to the vibration. This surely suggests that it is NOT the engine that is running unevenly - because the engine has now gone down to idling speed.
5 However, If you then slow down to (say) 25mph-30mph, the vibration disappears - or at least reduces to a really miniscule movement of the steering wheel, which perhaps you would not really be worried about.
Any ideas? Any help would be greatly appreciated. The obvious - i.e. balance the wheels - has already been tried. It made no difference whatsoever.

 

Have you checked the suspension for any play? I am also thinking that it might be worth checking the front wheel bearings and the brake rotors.

Best regards,

Thomas

 

Also check the ball joints at each end of the steering rack for excessive wear.
The ends are replacable.

 

If it is only happening after several miles, that might point to some front brake drag building up with some heat.
That alone should not create the deflection in steering, but worn rotors often cause a pulsing effect which if out of sync could deflect the steering wheel.

 

This may be unrelated but I had this very recent (expensive) experience.
All the rear bushes and control arms were replaced new last year.
I subsequently ran over a severe pothole. Whilst there was no observable driving issue, it failed the next Warrant and sure enough there was severe play in one of my new rear bushes. So one of the new control arms was replaced yet again.
I never observed a problem at low speeds, or up to 100kph motorway, presumably because the weight of the car kept things in place.
Just sayin'
(Oh, both left wheels ran over the pothole, and I was left thinking "is the steering wheel the same as before, just a smidgeon?". Turns out the steering angle was affected, because I also had some front bushes replaced at the same time and it's now perfect so wasn't my imagination)

Edit: I can't understand what cold has to do with it.
Also, bushes can't be tested by looking at them or wiggling. It needs a crowbar under the wheel, or that's what the Warrant of Fitness guys did.

 

This sounds like a bent rim to me. Sometimes the damage can be barely visible OR on the inside edge so you need an experienced rim repair shop to check them. Bent wheels can give very weird symptoms, only vibrating some of the time only under certain conditions. Also, I have had situations where 2 rims were bent and it was barely noticeable until they synchronised and then the wheel shake was incredible. Next corner it would go away for a while.

3 checks you could do: 1. Jack each side of the front off the ground and spin the wheels looking for the damaged area.
2. Increase front tire pressure by 3 to 5 pounds and see if the problem then happens even when cold. It might be that
a few pounds of increased pressure after the tires warm up is what makes the bend noticeable.
3. Rotate the tires front to back. You would still feel the bent rim but not through the steering.

Good luck and let us know how you make out.

Jeff

 

I believe H202Stream is right. I had some bad locked up calipers in front and a rear parking brake that was not disengaging fully.

Ended up with severe intermittent shake in steering and often after 10-20 minutes of driving.

I replaced my calipers, disks and pads and problem solved.

Maybe when you experience it, pull over to safe spot and touch rims near center. If any are very hot, might be a sign of drag. Careful though, don't burn s finger. Maybe buy a thermal heat gun that you point and it gives temp

Good luck

 

Did you get this fixed? I had a bad tire that would bulge when hot but was fine otherwise. It would almost throw the car off the road when it was warm after a few minutes of driving.

 

Thank you to all who responded. I am sorry that it has taken so long to get back to you. To all of you who suggested a brake issue particular thanks, as this indeed turned out to be the problem. Shortly after getting the replies to the thread, I felt the temperature of all the alloy wheels after a journey that had been long enough to cause the vibration to become apparent. The offside front wheel (nearside front in the USA) felt warm to the touch but the other three not so. When I put my fingers though to feel the disc (disc is what in the UK we call what in the USA presumably you call the rotor). It was really hot - you could only flick your fingers onto the disc for a fraction of a second, otherwise you would burn them. The other three discs were OK. It is easy to do this, as you can get your fingers in through the cut outs in the alloys. This clearly needed attention, irrespective of whether it was the problem. I have a friend who has a garage that repairs 'classic' cars owned by enthusiasts - generally cars from the 1950's and 1960's. Whilst my 2008 XJ6 (he calls it an X350 by the way) is not a classic car, he said that he would have a look at it for me. I took him on a road test and frightened him to death with the extent of the vibration at 50mph! When we got back to his place he measured the temperature of the four discs with a "gun" type of thermometer, pointing it through the cut outs in the alloys. The offside front disc was reading 300°C (sorry we use Centigrade here in the UK not Fahrenheit) and the others 25°C! He said that the piston in the calliper would be "sticking" causing the pads to rub on the disc. Anyway, he replaced the callipers and the discs and pads on both sides at the front (as the other side looked a bit dodgy as well) and hey presto - the problem has gone!!
As I say, thank you to all who responded.

 

Wonderful!! Glad you fixed it!! I know it is a wonderful feeling once the mystery is solvef.

If you plan to keep car and have the means, I suggest you rebuild the other three corners and have the electric parking brake checked and cables lubrucated.