Vibration at motorway speeds

[Phil Reid]

2001 2.2. diesel - 103,000 miles...

My car is suffering from the most annoying vibration at speeds above 70mph. Having had the wheels balanced several times, I thought that the only possible cause would be a buckled alloy wheel, but is it?

Above 70 mph the vibration worsens with speed, and feels like a pulsating shudder through the whole car. I am trying to think of the best way to describe it, and it's like when you're on a car ferry and they put the thrusters on in harbour - you feel a vibrating pulse through the ship's metal panelling (hope that makes sense). It seems to be there for a second or two, disappear for a moment, followed by a subsequent pulse and so on. The vibration is far worse when the car is fully loaded, and also worsens when the camber of the road makes the suspension dip to the nearside.

There is no noticeable vibration on acceleration, but there is some kick in the steering wheel if you release your hands. It probably is just a buckled wheel, (how do I find out which one), but before I buy a new set of alloys, could there be any other cause?

Thanks...

[stevoxsi]

Stick a spare on each corner in turn to see if that helps.

[bettyswollocks]

The undertray tight , could be coming down and shuddering at speed .

[Phil Reid]

Originally Posted by bettyswollocks

The undertray tight , could be coming down and shuddering at speed .

Thanks for the suggestion.

I had the same idea some months ago, but dismissed it out of hand.

Now that you've also suggested it I will remove the undertray and go on a test run down the motorway. There's no risk of damage to the sump etc. is there, as long as I don't go over uneven ground?

[john_h]

i had a vibration that would shake the whole car from 60mph onwards. i got new tires, balancing and alignment now no vibration.

but as you said you have already had this. i would check to see if your brake disks are warped. check your bearings. check the suspension is tight. also see if the rod ends have major play in them

[Phil Reid]

Originally Posted by john_h

i had a vibration that would shake the whole car from 60mph onwards. i got new tires, balancing and alignment now no vibration.

but as you said you have already had this. i would check to see if your brake disks are warped. check your bearings. check the suspension is tight. also see if the rod ends have major play in them

John,

What exactly do you mean by 'check the suspension is tight'?

[john_h]

ive seen people mentioning the bolts or somesort that holds the coils coming loose...i beleive betty may know more of what i am relating too.

[Phil Reid]

Originally Posted by john_h

ive seen people mentioning the bolts or somesort that holds the coils coming loose...i beleive betty may know more of what i am relating too.

I've bought some secondhand alloy wheels off Ebay and replaced the NSR. I'm 99% sure that this has cured the problem.