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Engine Vibration


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Hi all,

New here and already looking for advice! :notme:

 

History: 2000 Octavia 1.9dti 8V (90PS)

I'm getting vibration through the car at certain speeds. 

No issues or vibration through rev range when not in gear

Figure it's coming from the front so got the front wheels balanced - didn't solve it

Put the front of the car on jack stands and could re-create the vibration (~50mph)

Removed both wheels and could re-create the vibration - so not wheel balance issue. Hubs feel pretty tight - ball joints, control arms and bushes seem ok.

Looked under bonnet and engine appears to be vibrating (laterally, side-to-side)

 

That's as far as I've got. With no vibration in neutral I presume the flywheel, crank, etc are ok.

Anyone got any ideas what could be causing this? Could be clutch but my current prime suspect is the drive shafts (CV joints). I don't think it's engine mounts either - look ok (as much as I could see of them).

 

I was thinking of disconnecting the drive shafts for my next vibration test but I expect it's not easy to get them off?

 

Thanks!

Edited by quinlaned
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What condition is the dogbone mount in?.

 

 

Sorry - not sure what the dogbone mount is?

Just googled some images ... looks like an arm with bush to connect chassis to engine block?

Have only been under the car once and don't recall seeing it..... time to take another look!

 

I believe that the drive shafts are the "cause" of the vibration. Perhaps that vibration is normal and I have an issue with damping\bushes as you suggest?

 

Anyone got instructions for removing the drive shafts or replacing\maintaining CV joints?

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Dogbone is a reaction damper mounting for the whole power unit, it fits between the gearbox and crossmember and as such any minor transmission vibrations are hugely amplified if the rubber mount is worn. A bit more info here - http://www.briskoda.net/forums/topic/259926-dog-bone-mount-bush-change/?hl=%2Bdog+%2Bbone#entry3061744

 

If you think the shafts are at fault, securely raise the car and grasp the shaft and see how much up and down movement there is at each end by the joints to the gearbox and at the cv end. There should not be very much, and if there is, that could be a sign of impending joint failure.

 

It is also not unknown for bolts that retain the transmission mount to shear and cause vibrations - they are once only fit stretch bolts, although these failures are very small in number and may be just worth a check.

 

Hope it helps

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Many thanks Kentphil1. Appreciate your response.

Took a look under the car today. Dogbone is there alright! Looks intact but can see some movement in it when car\engine is vibrating. I'm going to replace it along with stretch bolts (OEM most likely) and see where that takes it. I did test the drive shaft cv joints for movement today (as you suggested), didn't get any noticeable movement .... 

 

Will report back once dogbone changed out.

 

Thanks!

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  • 3 weeks later...

I replaced the dog bone bush (oem) as suggested and it has made a significant improvement to the vibration I was experiencing. There is still some moderate vibration at certain speeds (close to 60mph). Some further investigation to do but for now I'm very happy :D.

Original dog bone looked fine physically but must have been weak .... fingers crossed that the new bush isn't just masking a separate issue!

 

Had a look at the exhaust mounts and they all seem ok.

Might consider changing the top engine mounts too ..... am I right that there are just 3 engine\gearbox bushes? 2 at the top and the dog bone?

 

Many thanks for much valued feedback & support :thumbup:

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I am having similar problems to this, 1.9tdi, it felt like engine was running on three cylinders at certain revs/speed I had engine checked out on computer no faults showing, when accelerating hard no problems but at around 60mph/1500/2000revs a slight judder at 70mph severe judder, dip the clutch smooth vibration stops, I am going to check all points mentioned above & will report back

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  • 3 years later...

Sorry to bring this thread back to life, but I've a dreaded vibration problem under acceleration, Octavia 2000 1.9 TDI 90hp. I've also searched a lot, changed a lot, but still there, only that this thread might be on the point.

 

History:

- bought the car, no vibration whatsoever except slight driveshaft wobble. The car also had a failed DMF and still didn't vibrate one bit.

-suspension is perfect, the prior owner changed every bushing, springs, shock absorbers, the car goes straight, no suspension noise.

- changed the DMF (with original LUK DMF complete set), driveshaft(s), gearbox oil, engine resealed

- after that major revamp the now car has this lurking and dreaded high frequency vibration under acceleration, isn't really noticeable up until 50-60km/h, then is constant in all gears and speeds above, as long as the engine is under load (acceleration), I went so far to change both driveshafts again (don't ask how I got them) but it's the same.

 

Only pattern I notice so far is that the vibration is almost unnoticeable when the engine is cold, as soon as it gets warmed up a bit, it's there.

 

What brought me here is that prior to resealing the engine, it was drenched in oil (leaking vacuum gasket, valve cover gasket, egr gaskets etc, all standard items), the dogbone mount was also covered in oil, my mechanic told me that oil could eat up the bushing. I now suspect the dogbone mount, because the symptoms are as described above, and maybe somehow during assembly of everything back together the dogbone failed and it is not visible by naked eye. Hence, cold bushing means firmer fit, no vibration, once it heats up it is loose?

 

How to check the dogbone mounts, or other engine mounts for that matter? And could this be the culprit, as I've changed almost everything, and the vibration wasn't there prior to taking the gearbox/dogbone mount down?

 

Mind you, the car has 320kkm on the clock, all engine/gearbox mounts seem original.

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  • 1 year later...
On 08/07/2018 at 10:58, Juka said:

Sorry to bring this thread back to life, but I've a dreaded vibration problem under acceleration, Octavia 2000 1.9 TDI 90hp. I've also searched a lot, changed a lot, but still there, only that this thread might be on the point...

 

...Mind you, the car has 320kkm on the clock, all engine/gearbox mounts seem original.

I have also similar problem as the post above me. It's 2009 octavia 1.9 77kw. BJB engine. 140.000kms. I havent touched anything yet, mine simptoms are also some periodical vibrations in idle when engine is warm, and also when starting warm engine it shakes more and takes a fraction of a second longer. The vibrations are not that strong, nobody driving with me even noticed anything yet but i notice them always as soon as they start

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