Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: The Cambelt Kid on 24 July 2007, 16:39:25

Title: A rumble from below...
Post by: The Cambelt Kid on 24 July 2007, 16:39:25
http://s164763218.websitehome.co.uk/omega/v6_1.mp3


Hi Chaps,

I wonder if I could pick your brains once again?  I have tried my best at trying to diagnose the problem myself but seem to have hit a brick wall…

I have a 52 plate 2.6 70k miles and just recently it has developed a noise under the bonnet.  It’s hard to describe exactly what it sounds like so I have included a link to an mp3 recording of it, oh the wonders of modern technology!  The recording was taken from my Zen MP3 player which was positioned next to the oil filter as this seemed to be clearest position.

Anyway a rattling noise can be heard quite clearly at tick over but soon dies away as the engine revs up and drowns the rattling out.  I don’t think it’s from either of the heads, nor either of the exhaust manifolds or manifold/down pipe gaskets.  The problem seems to come from the lower part of the engine around the gearbox/sump area??

The timing belt kit was changed at 44k but this was of the Goodyear brand and not GM.  The Goodyear reminder sticker under the bonnet states that a full timing belt kit was fitted.

I am really stumped on what this could be as my knowledge of the V6 engine is very minimal.  So any input on this would be a godsend.

Many thanks in advance.

Regards
Marc (Hoping and praying that it’s nothing big or expensive)   :(
Title: Re: A rumble from below...
Post by: ffcgary1 on 24 July 2007, 16:53:04
 Hi marc, sounds to me to be somthing like a valve ticking, poss oil pressure relife valve, marks dtm will tell you more though, Good luck.  :y
Title: Re: A rumble from below...
Post by: JasonH on 26 July 2007, 20:02:27
Sounds like a valve lifter to me. Try listening to the bolts on the cam cover with large screwdriver (one end on the bolt, one end to your ear).
Title: Re: A rumble from below...
Post by: The Cambelt Kid on 26 July 2007, 20:59:13
I was just looking for this on page 2/3 and though someone deleted it :o(

Anyway thanks for the input so far!  I will do as you say Jason - That sounds quite possible.  The noise sounds just as loud around the oil filter as it does from above but I can't seem to pinpoint it exact location.

I wonder if the timing between the two banks could be out at all.  I'm sure in the cambelt DVD video Mark mentioned that you can make adjustments to the cambelt assy to make the timing more accurate?  With this in mind I have also noticed a slight decrease in performance recently but I put this down to me getting used to the car after a few months of driving...
Title: Re: A rumble from below...
Post by: The Cambelt Kid on 26 July 2007, 21:10:25
In fact the car is on 70k now, maybe i should bite the bullet and change the timing belt?
Title: Re: A rumble from below...
Post by: Kevin Wood on 26 July 2007, 21:59:01
Quote
In fact the car is on 70k now, maybe i should bite the bullet and change the timing belt?

May as well. It's worth checking the cam timing and after stripping down to get at it you may as well just change it early for the sake of doing it again in 10K.

FWIW, the sound seems to me more like a blowing exhaust or just the pulses of gas in the manifold. Given that it was recorded down near the exhaust manifold it may well be  :-/

Kevin