Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: jamescropley on 02 January 2010, 00:16:42

Title: Horrible Rattle/Knocking from engine w/ throttle
Post by: jamescropley on 02 January 2010, 00:16:42
Happy New Year!

Unfortunately, mine is not as i have issues with my beloved omega.

Travelling back from Scotland earlier i noticed a horrible rattling sound coming from the engine. Pulled over at services to check it over and it sounds like a bag of nails rattling/massive knocking sound, whenever i accelerate although sits smooth when idle. Oil levels are fine and it literally started to happen with no warning signs.

Didn't want to risk driving so called out RAC. He said it could be the crankshaft...also noticed a pool of water on the floor when i had parked from the exhaust, smelt like almonds?? Is that coolant?

Anyhoo, just wondering what advice you could give me on this before i take it to the garage.

Many thanks! ;D
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: hotel21 on 02 January 2010, 00:24:33
When was the cambelt and tensioner last changed?  Possible impending failure...

But could also be the aux belt tensioner failing.  Use a spanner to remove the tension on the tensioner (there will be a bit in the maint guides, go have a look for yourself, please...) and remove the serpentine belt.  If, when restarting the engine, there is still noise, switch it off, as its probably the timing belt and tensioner thats guff.  If the noise is gone, probable aux belt tensioner but remember, the water pump and other bits are driven by this belt so could also be one of them....

Give it a look in the morning and report back.   :y
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: jamescropley on 02 January 2010, 19:35:50
Unfortunately, i cannot find the guide to do what you suggested so any help with the link would well, help :o)

The cambelt hasn't been changed whilst i have owned the car (17 months) and i have done around 20,000 miles in it.

I don't mean to sound rude but wouldn't the tensioner just give up rather than start to fail? I'm slightly ignorant in the mechanical department but from various bodies, ive been told hydraulic tappet faliure, big end, top end, broken rods etc...

Not sure wether its time to send the girl to the scrap yard in the sky....
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: Entwood on 02 January 2010, 20:43:32
Tensioner pulley bearings fail, vwery easy to check as said above .. single spanner on the centre nut, 15 mm I think... take the tension, slip the belt off. On mine I never bothered to start the engine as I could feel the pulley was knackered as I tried to spin it !!!

Pulley on its own is available from VX .. don't take their crap that you need the whole tensioner .. just change the pulley. Same bolt just undo it a bit harder after you've taken  up the tension.  10 minute job.... if the belt is in good nick.  If the belt has got damaged its a tad longer .. :)
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: RobG on 02 January 2010, 20:50:17
As above, check tensioner. Top L/H in pic of aux. belt routing
(http://i190.photobucket.com/albums/z257/belisensis/OMEGAFORUM/V6AuxBeltRoute.jpg)
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: dbr on 02 January 2010, 21:02:06
our tensioner bearing failed on the original engine. from 1st noise to complete failure was about 30 miles. wife stopped at shop the on restarting one big bang and many rattles as metal bits started to hit each other.  check the belts and bearings before starting. now I always change belt and pulleys at the same time (4yrs) as we only do about 6k / year
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: Selseybill on 02 January 2010, 21:03:53
To stop the rattle turn the heating up and then your knee's will stop knocking together. ::)
Seriously i hope it not to expensive to fix
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: Kevin Wood on 02 January 2010, 21:46:07
Exhaust manifold blows can often sound like a knocking noise, and are very sensitive to engine load...

Kevin
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: feeutfo on 03 January 2010, 01:58:21
from your description it sounds more seriuos than failed aux belt tenssioner to me. But i do hope i'm wrong.

Personally would not start the engine until the its been turned over by hand( ratchet on the crank pulley) with the cam belt cover removed so as to expose the tensioner and timing marks. If that looks ok crank it on the key with a quick flick, and see what you have, then go from there
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: Bionic on 03 January 2010, 05:14:35
Hiya,
First thing I would look at, cos I had this trouble with mine, would be the Anti-Knock sensors. If one or both fail you will get a terrible clattering (known as 'pinking' or pre-ignition) as you accelerate which them goes away until you next accelerate.
They are not expensive to replace and not too difficult either.
My right side bank one had had its wire chafed through by it not being correctly routed by the previous owner after some work had been done. Fortunately I was able to repair it and so negate having to change it. Its never troubled me again now it is correctly routed!
Almondy smell from the exhaust usually indicates a catalytic converter on the way out! Have an emmissions test at a local garage. Water from the exhaust happens on mine too and is just condensation from the hot exhaust gasses hitting the colder air then turning back to water. Its why exhusts rot from the inside!
GudLuk
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: jamescropley on 03 January 2010, 21:30:44
Hi guys.

I appreciate all the replies I have received concerning this matter.

I have checked the tensioner as described but everything seems ok.

The noise (if this helps) is coming from the top right of the engine casing. Only slight when idle but at revs gets louder and obviously more frequent.

If anyone is local (I'm in Grantham) I would gladly slip someone a tenner for a quick look and their opinion  :D


Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: TheBoy on 04 January 2010, 09:18:15
Quote
Hiya,
First thing I would look at, cos I had this trouble with mine, would be the Anti-Knock sensors. If one or both fail you will get a terrible clattering (known as 'pinking' or pre-ignition) as you accelerate which them goes away until you next accelerate.
They are not expensive to replace and not too difficult either.
My right side bank one had had its wire chafed through by it not being correctly routed by the previous owner after some work had been done. Fortunately I was able to repair it and so negate having to change it. Its never troubled me again now it is correctly routed!
Almondy smell from the exhaust usually indicates a catalytic converter on the way out! Have an emmissions test at a local garage. Water from the exhaust happens on mine too and is just condensation from the hot exhaust gasses hitting the colder air then turning back to water. Its why exhusts rot from the inside!
GudLuk
If the knock sensors (or most likely their wiring), the ECU detects this an retards the ignition to prevent preignition, and pops on the EML as well.  EML may not pop on until above 2k.
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: TheBoy on 04 January 2010, 09:18:45
Quote
Hi guys.

I appreciate all the replies I have received concerning this matter.

I have checked the tensioner as described but everything seems ok.

The noise (if this helps) is coming from the top right of the engine casing. Only slight when idle but at revs gets louder and obviously more frequent.

If anyone is local (I'm in Grantham) I would gladly slip someone a tenner for a quick look and their opinion  :D


When you say tensioner checked, is that the aux tensioner or the cambelt tensioner?
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: jamescropley on 05 January 2010, 19:11:18
Hi Guys,

Just to close to this question, i took the car to my garage yesterday and my crankshaft has buggered so being a 10 year old car, it has gone on ebay for spares etc. Too expensive to repair :(

Thanks for your help :)
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: feeutfo on 06 January 2010, 03:00:16
Quote
Hi Guys,

Just to close to this question, i took the car to my garage yesterday and my crankshaft has buggered so being a 10 year old car, it has gone on ebay for spares etc. Too expensive to repair :(

Thanks for your help :)

sorry to hear James, but thought it was top end? what did he say? any details?
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: jamescropley on 06 January 2010, 19:07:48
Didn't really give any details, he just said that the crankshaft had "gone" and would be quite expensive to replace.

After weighing up factors it just seemed to costly to repair.

I am looking for another omega now as ive been bitten by the bug!
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: JamesV6CDX on 06 January 2010, 19:51:38
Quote
Didn't really give any details, he just said that the crankshaft had "gone" and would be quite expensive to replace.


If the crankshaft had "gone" I suspect the pistons would have flown out of the bonnet by now  ;D or at least engine seized...

I bet it's a cambelt tensioner/lifter, etc....
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: JamesV6CDX on 06 January 2010, 19:52:15
Ask him to explain the mode of failure he suspects, and how he arrived at said conclusion...
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: jamescropley on 07 January 2010, 03:23:34
I think i'll get a second opinion then. Don't really want to be spending upwards of a grand on a new one atm...
Title: Re: Horrible Rattle/Knocking from engine w/ throttle
Post by: The Red Baron on 07 January 2010, 05:31:33
i would deffo get a second opinion, as said, sounds like cambelt tensioner & its let the belt slip to me.