W124 Vibrates at Motorway Speeds

[Mercmartin]

My K-reg W124 estate (320 TE) suffers from vibrations at motorway speeds.
Before I have this investigated, I am wondering if anyone could give me some pointers as to what might be causing this. Advice and ideas would be gratefully received!

Here's some background:

I recently took it for an outing to France. On the smooth motorways there, there is a noticeable vibration throughout the car when it's driven at motorway speeds. At 70 m.p.h. I can only just feel it; at 80 it's clear, although not so forceful I feel there was any immediate danger.

I am unable to "drive through it", it gets worse the faster I go. I can feel it in the steering wheel, but also the rest of the car, so it's difficult to tell if it's coming front the front or rear.

I first noticed this in August last year, on my first outing with it to France, but his time it seemed slightly worse. Also, coming back I had a heavy load which seemed to aggravate it slightly.

Between these continental outings, I have had a bit of work done to the suspension: new linking arms (if I recall correctly - don't have the bill in front of me, I’m afraid...) to the front left, and new shock absorber to the rear right. The vibration was not investigated, but nor was anything picked during these repairs. The car has the sport suspension and hydraulic self levelling system.

Before the latest trip, I had the rear wheels re-balanced, but this hasn't helped. Wheel alignment appears to be fine.

 

[television]

I think that you problem is with the engine mounts that have sunk, and this throws the drive chain out of line.

Other things are the propshaft center bearing and the flexible couplings

 

[Bolide]

I'd start at the front and work backwards. I'd suspect front balljoints (these will need replacing sooner or later), broken springs, out-of-balance warped or bent front wheels, deformed tyres, accident damage, worn bushes in the front suspension and worn engine & gearbox mounts. It might need a new steering damper - but you have to ask, why the car is vibrating at all?

If you find nothing on a visual inspection I'd try a new set of tyres and have the rims checked very carefully before fitting

Nick Froome
www.w124.co.uk

 

[wireman]

In addition to the checks suggested above do a very close examination of the rear suspension links for wear and tear, take extra care to examine the four sub frame mounting bushes with particular emphasis on the front pair. The sub frame mounts should provide positive location of the frame in all three axes, the front pair take a considerable amount of hammer in harsh acceleration and hard braking, with these mounts in a tired state the sub frame can wander just enough to make the car feel wrong and there may be some bumping and thumping going on under harsh driving.

 

[Juddian]

Had similar on my 320te, had my indy go through it, could find nothing wrong, changed back to my summer wheels and tyres, vibration gone. But the tyres and wheels looked fine and balanced ok.

Have you got someone with a similar car near you who could swap wheels for a day to test this out before you start expensively chasing down this problem?

At least that irons out the wheel situation then.

 

[Bolide]

I agree and would immediately suspect tyres

The wear pattern on the tyres may tell you everything you need to know. If any of them has worn assymetrically then there is an immediate clue. If the front tyres are conical there's another. If the front tyres are feathered in their appearance - in other words if the rubber is rough and torn-looking - then something's loose & vibrating

Someone who knows W124s should be able to find at least one problem in a couple of minutes. Someone who doesn't will start changing parts till they hit on the right solution

I suspect you have more than one problem

Nick Froome
www.w124.co.uk

 

[star]

Apart from whell balance, get them checked at a different garage 1st, then check prop bolts are tight on the prop couplings and that they don't have excessive play, also check centre prop bearing/carrier for play/wear. Arms and joints would not necessary give you a vibration, more knocking or wondering.

 

[and11]

I think that you problem is with the engine mounts that have sunk, and this throws the drive chain out of line.

Other things are the propshaft center bearing and the flexible couplings

My engine mounts, and front propshaft doughnut were shot, but only vibration and knocking was on start up and off. Prop doughnut made a thumping sound from under car on acceleration.

 

[kth286]

Mercmartin

I suspect that you may have had a new wishbone replaced on the front nearside.

Please check that.

If so why was it replaced ? Worn bushes probably. Which causes vibration, because the geometry cannot be correctly set, because the car is in a different state static, compared to driving state.

Now if you did have a new wishbone, the car geometry then needed to be set up straight away after that, because there is no way the fitter would know by sight how to fit the new part as it has two adjusting bolts as part of the fitting of it.

So my guess is the geometry is well out, but that you may not have done enough miles for the tyre wear to be showing yet, OR you have not properly looked at the very inside of each tyre to see the wear.

Where you based ?