W211 E320 V6 petrol - vibration

[grahamwoodward]

Hi guys. I have a 2004 E320 (W211) with 151,000 miles on the clock. When I start off from cold there is a vibration through the floor of the car. It goes away somewhat when the car warms up but not totally. I suspected that the engine mounts need replacing but my mechanic says there is no movement in them at all.

Does anyone know if when they go and cause vibration, do they have to have any movement as such?

Does anyone know what else it could be? It's not the propshaft or low gearbox oil; these have been checked.

Thanks

 

[LostKiwi]

If the mounts have never been changed it's a good place to start. They're hydraulic and over time the oil can leak out.

 

[Wighty]

i can’t believe that at 151,000 the engine mounts and the prop shaft mount don’t need replacing .
What about low gearbox oil , that when warm increases in volume and then behaves itself ?
When was the last ATF and filter change ?

 

[grahamwoodward]

Wighty - gearbox is serviced every 40k and was checked recently - all A-OK. No leaks from engine mounts but I'll probably start with the gearbox mount, as I believe you have to remove the speed-sensitive steering rack to get to the engine mounts.

 

[mattkh]

Hi guys. I have a 2004 E320 (W211) with 151,000 miles on the clock. When I start off from cold there is a vibration through the floor of the car.

I take it that there is no vibration of the engine when idling on a cold start..?

 

[grahamwoodward]

Mattkh - no, nothing. When I say vibration I mean a sort of roughness through the floor, not a rattling sort of vibration. Usually these M112 V6 engines are silky smooth, as was mine until recently. On the motorway its OK but there is a small amount of vibration when you press hard on the loud pedal. Everything points to the engine or gearbox mount; it's just that my mechanic said there was no movement in the mounts. The engine or gearbox don't rock when you pull away like Ford mounts used to when worn.

 

[mattkh]

So, say you are cruising at 60mph without any roughness and you press the gas pedal to speed up to 70mph, then you feel the roughness.
How long does the roughness last..?

 

[grahamwoodward]

It's there all the time but less obvious on the motorway. Acceleration is harsher than it used to be.

 

[00slk]

You can self check the engine mounts.
Lift the bonnet to its highest point, get in to the car and start it up. Keep the handbrake applied, select drive and slowly push down on the accelerator pedal and increase the engine revs. If the mounts are worn you will see the engine raising up quite significantly. If your handbrake wont hold put your left foot on the foot brake just as an extra safety measure.

 

[grahamwoodward]

Thanks 00slk - I'll try that tomorrow.

 

[00slk]

Thanks 00slk - I'll try that tomorrow.

I tried this on my 55not long after I bought it and was surprised just how much the engine lifted. Fitted new mounts, including the gearbox mount and all was good.

 

[grahamwoodward]

Update: No movement in engine mounts so had the gearbox mount replaced to day. What a difference. No vibration, much smoother, almost as it was when I first got the car 7 years and 95,000 miles ago. Garage said that it was a bit soft when they took it off, so needed doing. If you have similar vibration I recommend you start with this replacement first - only a £25 part. Cheap at twice the price. Thanks everyone for the advice. Keep Safe.

 

[grahamwoodward]

EXTRA, EXTRA READ ALL ABOUT IT: Well, three months later and I've now had the engine mounts replaced - What a difference. Although there was no movement of the engine when tested on a ramp, when they were removed, both were split and fit for the bin. Now the car is like brand new. So, So, So much better.
Moral - if you have any vibration from an M113 engine and the gearbox mount doesn't solve it - replace the engine mounts. My mechanic also said that the genuine Merc parts are ten times better than pattern parts, even though they are over £90 each.

 

[mattkh]

Thanks for the update and advice.
So happy for you.