Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: miggy on 12 November 2007, 14:32:18

Title: Strange vibration
Post by: miggy on 12 November 2007, 14:32:18
Over the past week i have noticed that whilst doing approx 30mph there has been a slight vibration going through the car, this is only when she is first driven in the mornings on the way to work.

This morning it was worse than ever, its as though your driving over rumble strips, not as bad as that, but a rumble.

This morning was very cold -2, could it be the gearbox oil, i dont know, would any of you guys know what it could be, or have you heard of this symptom before.

The rumble goes once she is warmed up, I only had it slightly just now on the way home, no lights are showing as a problem.

Any suggestions.

 :-/ :-/

Just a thought, could it be the rear shocks. :question :question
Title: Re: Strange vibration
Post by: Kevin Wood on 12 November 2007, 17:35:38
I've noticed this too. There was a thread on it about 6 months ago IIRC.

My theory is that it's propshaft vibration (nothing else runs fast enough to vibrate at only 30MPH) and that it occurs because the rubber doughnut coupling gets distorted when the car is parked with some torque load on it (auto gearbox in park).

Once the coupling has flexed a bit, and warmed up, it regains its shape and the vibration goes.

That's my theory anyway.

Kevin


Title: Re: Strange vibration
Post by: miggy on 12 November 2007, 17:39:54
Quote
I've noticed this too. There was a thread on it about 6 months ago IIRC.

My theory is that it's propshaft vibration (nothing else runs fast enough to vibrate at only 30MPH) and that it occurs because the rubber doughnut coupling gets distorted when the car is parked with some torque load on it (auto gearbox in park).

Once the coupling has flexed a bit, and warmed up, it regains its shape and the vibration goes.

That's my theory anyway.

Kevin



Hmmmm, i always put the car into Neutral, apply handbrake then put into park, so no load on the shaft, wonder if the cold could be a factor on the rubber doughnut.

 :-/ :-/ :-/
Title: Re: Strange vibration
Post by: Kevin Wood on 12 November 2007, 17:47:54
Yeah, I do that too, and it doesn't cure it.  :-/

Maybe it's a cold autobox? I certainly get it, and if you shift it into neutral, it stays there, and it's related to car speed. Propshaft or the back end of the autobox is all it can be.

Kevin
Title: Re: Strange vibration
Post by: miggy on 12 November 2007, 17:54:19
Quote
Yeah, I do that too, and it doesn't cure it.  :-/

Maybe it's a cold autobox? I certainly get it, and if you shift it into neutral, it stays there, and it's related to car speed. Propshaft or the back end of the autobox is all it can be.

Kevin


Do you find it to be there more, the colder the mornings, do you think changing the auto box oil for a different type would help.

 :question :question :question :question

Open to suggestions as this morning it was bad, surely it should not do this.

Title: Re: Strange vibration
Post by: Kevin Wood on 12 November 2007, 18:02:09
It's certainly worse when it's cold because I had it quite a bit when the car was new to me (January / February) and have only noticed it again recently.

Quote
do you think changing the auto box oil for a different type would help.

Depends if it is the auto gearbox :-/

Maybe it's just the weight of the propshaft on the rubber couplings that pulls them very slightly out of shape? Once they're up and running the colder they are the harder they are and thus the worse the vibration, until they warm up...

Kevin
Title: Re: Strange vibration
Post by: scog on 12 November 2007, 18:14:01
hi
dont know whether this helps
but i have a ford scorpio as well as the omega and what you have described is called cattle grid effect on the scorpio if you change the oil it helps in the short term but it is usually terminal for the auto box look for fine pieces of metal in the oil when you change it
mark
Title: Re: Strange vibration
Post by: miggy on 12 November 2007, 18:19:11
Quote
hi
dont know whether this helps
but i have a ford scorpio as well as the omega and what you have described is called cattle grid effect on the scorpio if you change the oil it helps in the short term but it is usually terminal for the auto box look for fine pieces of metal in the oil when you change it
mark

That just about rounds off the day for me, now i have a cow problem. ;D ;D

Hope it aint, thanks for the info. :y :y :y
Strange its only when cold.
Title: Re: Strange vibration
Post by: cem_devecioglu on 12 November 2007, 18:37:48
When cold in the morning I also have the same problem but this disappear within half a km..Mine is 97 model at 82000..

edit : in haynes manual they list these reasons

worn constant velocity joint
worn universal joint
distorted or bent propeller shaft

for vibration when acceleration
Title: Re: Strange vibration
Post by: miggy on 12 November 2007, 18:40:21
Very strange, never had this on my other auto miggys

 :-/ :-/ :-/ :-/ :-/ :-/