Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: megaomega123 on 26 June 2007, 18:08:25

Title: Knocking?
Post by: megaomega123 on 26 June 2007, 18:08:25
Labouring in 2nd gear at around 10-15 mph I get a deep knocking noise. I can only liken it to the clonking of a driveshaft taking up slack. It seems to be coming from the front centre. Any gearbox issue causing this?
Title: Re: Knocking?
Post by: TheBoy on 26 June 2007, 18:53:23
Big Ends ?  :'(
Title: Re: Knocking?
Post by: megaomega123 on 26 June 2007, 19:49:16
Big ends :'(  That's a bye bye engine yes?
Title: Re: Knocking?
Post by: megaomega123 on 26 June 2007, 19:49:53
Anyway of testing to confirm?
Title: Re: Knocking?
Post by: cdx25 on 26 June 2007, 20:54:31
Quote
Anyway of testing to confirm?

Could well be big ends, does it knock at any other time?  ie at idle?  when you blip the throttle quickly to say 2500 rpm can you notice it?  

indirect stuff: is it high mileage?  known to have run low on oil?   low oil pressure?

Any other noises?
Title: Re: Knocking?
Post by: megaomega123 on 26 June 2007, 21:49:06
Quote
Quote
Anyway of testing to confirm?

Could well be big ends, does it knock at any other time?  ie at idle?  when you blip the throttle quickly to say 2500 rpm can you notice it?  

indirect stuff: is it high mileage?  known to have run low on oil?   low oil pressure?

Any other noises?
No noise at any other time. Idles perfectly. 87000 miles only bad thing is not changing oil regularly. I changed it today and it came out relatively ok, no bits and bobs, just dark oil.

This is why my 1st suggestion was gearbox related as the engine does not replicate the noise when not under load. From 1000-6000 rpm no noise.  
Title: Re: Knocking?
Post by: Dazzler on 26 June 2007, 21:52:32
Pinking???? If you put it in 5th at about 30mph and floor it does it still do it??? Could be pinking, lack of oil changes does not help this, that and cheapo fuel....
Title: Re: Knocking?
Post by: TheBoy on 26 June 2007, 21:54:53
Quote
Quote
Quote
Anyway of testing to confirm?

Could well be big ends, does it knock at any other time?  ie at idle?  when you blip the throttle quickly to say 2500 rpm can you notice it?  

indirect stuff: is it high mileage?  known to have run low on oil?   low oil pressure?

Any other noises?
No noise at any other time. Idles perfectly. 87000 miles only bad thing is not changing oil regularly. I changed it today and it came out relatively ok, no bits and bobs, just dark oil.

This is why my 1st suggestion was gearbox related as the engine does not replicate the noise when not under load. From 1000-6000 rpm no noise.  
Obviously, not changing oil is not going to help the engine...
Title: Re: Knocking?
Post by: megaomega123 on 26 June 2007, 22:15:22
Quote
Pinking???? If you put it in 5th at about 30mph and floor it does it still do it??? Could be pinking, lack of oil changes does not help this, that and cheapo fuel....

30mph 5th gear floored it, no problems, slow climb to 50 then normal. Only seems to be in 2nd gear at 10 mph in tesco carpark lol.
Doesn't seem engine related at all.  
Title: Re: Knocking?
Post by: cdx25 on 26 June 2007, 22:23:31
Going to be more tricky to fault find if you need to be moving to produce the noise.  

I rebuilt an engine a while back (not Vx) that had a knock which turned out to be detonation on pot 5. Came across this http://www.misterfixit.com/deton.htm a while back which might be of interest.

Can you post a recording of the noise?  Could put a recorder in the engine bay and then provoke the noise?  Better doing that once than repeatedly provoking it and listening!
Title: Re: Knocking?
Post by: cdx25 on 26 June 2007, 22:26:05
Quote
Quote
Pinking???? If you put it in 5th at about 30mph and floor it does it still do it??? Could be pinking, lack of oil changes does not help this, that and cheapo fuel....

30mph 5th gear floored it, no problems, slow climb to 50 then normal. Only seems to be in 2nd gear at 10 mph in tesco carpark lol.
Doesn't seem engine related at all.  

Shop elsewhere?  ;D
Title: Re: Knocking?
Post by: Danny on 26 June 2007, 22:31:10
strange.. omega's are usually fond of tesco car parks!
Title: Re: Knocking?
Post by: megaomega123 on 26 June 2007, 22:31:20
Quote
Going to be more tricky to fault find if you need to be moving to produce the noise.  

I rebuilt an engine a while back (not Vx) that had a knock which turned out to be detonation on pot 5. Came across this http://www.misterfixit.com/deton.htm a while back which might be of interest.

Can you post a recording of the noise?  Could put a recorder in the engine bay and then provoke the noise?  Better doing that once than repeatedly provoking it and listening!

Thanks for that. It seems to be more underneath the car than up front. It sounds like a cv joint but more central. Sorry to be so vague but it is hard to pinpoint and hard to provoke.
Title: Re: Knocking?
Post by: megaomega123 on 26 June 2007, 22:33:00
Tesco is the only place I can get it to happen. It's the only place I can go slow enough in 2nd gear to replicate it.  ;D
Title: Re: Knocking?
Post by: Dazzler on 27 June 2007, 09:15:08
Prop shaft bearing slack, or sloopy drive train?????????
Title: Re: Knocking?
Post by: megaomega123 on 27 June 2007, 12:08:48
Quote
Prop shaft bearing slack, or sloopy drive train?????????

Prop shaft bearings is spot on as in the area of the noise. Could you elaborate on sloppy drive train in laymans idiots terms?

Thanks
Title: Re: Knocking?
Post by: Varche on 27 June 2007, 14:49:19
Maybe I am an auto hypocondriac but I think my car has the same thing. The noise sounds like "bunk" and comes from centre of car near gear change but only at low speeds and when it chnages up or down a gear - not all the time either just on a certain section of our local road. I'll be interested in the outcome.

In a few days time I am going to get the car up in the air to have a look at the exhaust and change the fuel filter. I'll have a look at the drive train and look out for any sloppy bits! Oh joy.

olive

Title: Re: Knocking?
Post by: megaomega123 on 01 July 2007, 16:03:01
Just an update to this. The knocking was from the passenger side drop link. DaveL provided the spare and Hotel21 fitted it. Peace at last  :y