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Omega Help Area => Omega General Help => Topic started by: jamescropley on 31 May 2010, 20:20:55

Title: Knocking noise from engine whilst travelling
Post by: jamescropley on 31 May 2010, 20:20:55
Hi everyone.

Hopefully someone can help me on this.

Last week I noticed a rattle coming from the exhaust (cat area) that was noticeable at low speeds (town driving) but went away at high speeds.

I've done over 700 miles this weekend and the noise has gone, however, there is now a very loud knocking/clonking noise that is apparent from driving at low speeds and becomes louder when the clutch is pressed. It dissapears when I apply the brakes and also when I get to around 30mph.

I'm not sure if the exhaust I first had has had a knock on effect after having done a lot of mileage.

Any help would be greatly appreciated.

James.

When I
Title: Re: Knocking noise from engine whilst travelling
Post by: same #same# on 31 May 2010, 20:24:32
sound bit like a loose plate or shield
Title: Re: Knocking noise from engine whilst travelling
Post by: Mr Skrunts on 31 May 2010, 20:31:57
yeah, loose heat sheild on the cat.
Title: Re: Knocking noise from engine whilst travelling
Post by: jamescropley on 31 May 2010, 21:31:21
That was my 1st thought but, I've had heat shield probs before and this is a totally different sound :(

With the knocking/clanking, it's a very dull noise, not a rattle, so that kind of eliminates the heat shield idea but of course I welcome any relpy.

I'm just a little bit puzzeled as why the noise goes when accelerating and when the brakes are applied.

I'm actually thinking it could be clutch related as the noise is louder with the clutch pedal pressed but what throws me is that it is there also with it not being pressed. Nightmare!
Title: Re: Knocking noise from engine whilst travelling
Post by: Kevin Wood on 31 May 2010, 22:37:29
Dual mass flywheel issue, perhaps?

Kevin
Title: Re: Knocking noise from engine whilst travelling
Post by: jamescropley on 02 June 2010, 17:51:43
Right, it's been at the garage today and his diagnosis is that the cat has gone and needs replacing, although he said he can't be entirely sure until it is replaced.

I've had cats go before and familiar with the horrible rattle that comes with it but this is a totally different sound.

Anyone have any thoughts? I don't want to spend a couple of hundred quid on something that wont resolve the issue.

James
Title: Re: Knocking noise from engine whilst travelling
Post by: same #same# on 02 June 2010, 18:04:22
test cat with rubber mallet, it would rattle with that and not damage it, have a slow drive down a bumpy road plenty in lincs see if sound come up then.
Title: Re: Knocking noise from engine whilst travelling
Post by: jamescropley on 02 June 2010, 23:34:12
Right, after much head scratching and 20 bensons trying to figure out just what was wrong, i had a feeling the noise was coming from the drivers side wheel.

I went to tighten the bolts after reading a thread from another car forum and two of the bolts were hanging on by a thread, tried to tighten them up and they have sheared off, leaving half of the bolt inside the hub. Seems like the muppet who had the car before me has crossed the threads in the wheel and they have come loose.

Took for a short spin and the noise has dramatically reduced.

I'm thinking that it could now be a knackered hub that created the knocking.

Back to the garage in the morning!

Title: Re: Knocking noise from engine whilst travelling
Post by: jonnycool on 03 June 2010, 00:00:36
Quote
Right, after much head scratching and 20 bensons trying to figure out just what was wrong, i had a feeling the noise was coming from the drivers side wheel.

I went to tighten the bolts after reading a thread from another car forum and two of the bolts were hanging on by a thread, tried to tighten them up and they have sheared off, leaving half of the bolt inside the hub. Seems like the muppet who had the car before me has crossed the threads in the wheel and they have come loose.

Took for a short spin and the noise has dramatically reduced.

I'm thinking that it could now be a knackered hub that created the knocking.

Back to the garage in the morning!

Saved yourself a few quid there mate, good thing you found the problem before it did you some serious damage  :y
Title: Re: Knocking noise from engine whilst travelling
Post by: Kevin Wood on 03 June 2010, 11:05:57
Quote
Back to the garage in the morning!

.. ad different garage to the one who diagnosed the cat, I hope!

Kevin
Title: Re: Knocking noise from engine whilst travelling
Post by: jamescropley on 07 June 2010, 21:06:33
Just to let everyone know, the culprit of the noise was the fact that the wheel bolts were missing.

Replaced the whole hub and brake disc earlier, that's s job and a half!

Now running smooth with no knocking noise...Cat indeed?!
Title: Re: Knocking noise from engine whilst travelling
Post by: RobG on 07 June 2010, 21:10:16
Quote
Just to let everyone know, the culprit of the noise was the fact that the wheel bolts were missing.

Replaced the whole hub and brake disc earlier, that's s job and a half!

Now running smooth with no knocking noise...Cat indeed?!
Job`s a doddle as long as you got a breaker bar on the hub nut ;)