Vibrations within Cabin - Esp Passenger Seat

[S3 CYP]

Afternoon All,

Looking for some helpful advice and hopefully pointed in the right direction to solve an issue that has arisen with my 2002 AMK S3 with 90,300 miles.

I have tried the search last night and searched for hours and hours but all the search was returning was vibrations at idle and general missfiring - nothing relating to what I seem to have problems with.

Backround Info

Purchased the car 18 months ago and have had 10,000 miles of trouble free driving so far. I wanted move away from the longlife service as the previous owner did mainly motorway miles so it was ok for him - I wanted to change the oil every 5000 - 6000 miles, in addition to this, using 5w30 oil it seemed to be drinking the stuff (car checked over and no visible leaks) - so after reading the mainy oil posts on here I opted to go with 5w40 in the hope that it would not drink so much.

So I purchased the oil, filter and sump plug and on with the oil change - after 1000 miles - the oil level is the at the correct level with no loss so far - so all is good on that front - if on 5w30 it would have needed a top up by now.

One thing I noticed when I started the car after the oil change was that the oil pressure light did not come on the dash (as it states it will do on in the service manual) so I left the car idling for 15-20 minutes, shut her down then re started still no light so I left her for a few hours then added a slight top up - should I be concerned that the light did not come on?

The Problem/Issue

I have been told by two different people sitting in the passenger seat that they can feel vibrations thought the seat that was not there before - all after the oil change ( I have also sat in the seat and I can feel the vibrations aswell on idle)

I have replaced all the vacuum lines with silicone except for the PVC hoses (inpected these and no holes) and the car drives fine boosts as it should.

I am thinking it could be a one of the following (or more) - fuel filter/pump , engine/gearbox mounts, oil punp blocked/faulty, throttle body or plugs which were changed 6000 miles ago but I have not had a chance to have a look at them yet.

I am I going own the right road or have I completely misssed something !

Also I did not use vagcom (dont have it - YET) when I did the oil change but I have the liquid and nothing showing up on there - is it required for an oil change?

Any help would be wonderful on this one.

Chris

 

[JD09]

Could you have hit a pothole and the fact that the issue started after the oil change is purely coincidental?

I would look in to tracking, tyre and wheel issues first.

 

[Welly]

I totally agree. Other than an engine mount, it's unlikely the be engine related. More likely to be transmission.

Check balancing most specifically.

 

[vetch]

I don't think tracking or balancing would cause a vibration when idling.

 

[Welly]

I don't think tracking or balancing would cause a vibration when idling.

Ah, didn't read that.

Check the dog bone rear engine mount. Thats the likely culprit. It's over towards the passenger side as well so it makes sense. Common for going - I had to replace mine.

 

[JD09]

Ah nor did I, apologias!

I would be tempted to say dogbone mount aswell, colleague had one go in his old S3 and I know he was a much nicer person in the morning after he had had it sorted!

 

[S3 CYP]

Many thanks for the replies most helpful.

Had 4 new tyres, tracking and alignment done 500 miles before the change so I have ruled that one out.

I have a look at the dogbone mount as suggested and hopefully solve the problem.

Thanks again all.