Vibration at about 1600rpm

[dan_b]

Noticing recently that the car is making a fair fuss when pulling through 1600rpm. It's a low-frequency shake/vibration which of course goes away as revs increase but it's quite intrusive. Could this be a gearbox or engine mount bush wearing out? Any suggestions?

 

[Birchall]

Noticing recently that the car is making a fair fuss when pulling through 1600rpm. It's a low-frequency shake/vibration which of course goes away as revs increase but it's quite intrusive. Could this be a gearbox or engine mount bush wearing out? Any suggestions?

Hi Dan is it just in 1st? Just when accelerating? Coasting?
Do you feel it more through the steering wheel or gear level (or backside!)


Steve B

 

[dan_b]

It's more noticeable in 2nd or 3rd and only when accelerating. It's a butt-shaker, you feel it in the chassis rather than through the steering or gear stick.

 

[Birchall]

Could it be a buckled wheel perhaps?

Steve B

 

[Birchall]

Noticing recently that the car is making a fair fuss when pulling through 1600rpm. It's a low-frequency shake/vibration which of course goes away as revs increase but it's quite intrusive. Could this be a gearbox or engine mount bush wearing out? Any suggestions?

Just remembered you have changed your wheels recently !

Are they all tight?
(said he, clutching at straws)

Steve B

 

[dan_b]

I will check them, but it doesn't feel like a "wheel wobble" type vibration - I've had those in the past.
It feels a bit like a transmission vibration - it's a bit like when on my S2 quattro I'd replaced the rear diff rubber mounting with a so-called better "Powerflex" bush, which all that seemed to do was transmit far more NVH through from the diff into the chassis.

I'm hoping it's not the gearbox about to tear itself apart!

 

[Birchall]

I'm hoping it's not the gearbox about to tear itself apart!

You are not alone there!!!

But was there any sign before you changed the wheels and was there any vibration after the swap at all, before this started?

Steve B

 

[a2sumo]

Isnt 1600rpm the point that the actuator is coming in on the turbo? Could it be sticky or a vac leak? Just an idea. Mike

 

[dan_b]

It's a good question. It's got more noticeable since swapping the 16s back on, but was there with the 15s too but less so. It makes the left-side of the dash rattle as well.

You are not alone there!!!

But was there any sign before you changed the wheels and was there any vibration after the swap at all, before this started?

Steve B

 

[Birchall]

It's a good question. It's got more noticeable since swapping the 16s back on, but was there with the 15s too but less so. It makes the left-side of the dash rattle as well.

If it was the gearbox causing significant vibrations I would have expected mechanical noises from it.

Engine mounts might be the cause, it would normally be worse when not on load (not accelerating hard) and not on the overrun (because when accelerating and on the overrun the engine is pushed hard against the mounts, taking up any slack) and then kicking in as acceleration peaks a little (i.e. no significant load on the engine mounts)

I would contact Gary's colleague (from the number on the top of the last invoice you had) Gary is away this week.

But get his mate to check it out for you ASAP just in case (he is a fully trained Audi mechanic!)

Steve B

 

[dan_b]

Ok, so the vibration is over a wider RPM range than I originally thought - always comes on around 1400RPM and up to 1600RPM and is much more noticeable in higher gears.
Used to be the case that I could bimble at 40mph in 5th along dual carriageways, and now this is incredibly unpleasant. It's not like I'm using full-throttle at these lower RPMs either.

Does this suggest engine/gearbox/dog-bone mount?