Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: Mr.OmegaMan on 06 December 2015, 20:16:59
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Engine running nothing else on not even the heater, engine up to temp etc.. Quick Rev sounds normal...
Turn heater on quick Rev slight difference in sound from the engine like a muffled grinding sound..
Heater, lights, heated seats ON etc.. and the grinding type sound is much louder.
(I'm probably describing the sound completely wrong)
To me it sounds like an alternator problem..?
The alternator went completely around 2 years ago and tbh the sound does sound familiar from that time but it was much worse then and it went completely at that time, I had it refurbished. Been fine since then. Till now obviously.
The batter is approx 11 months old from CP4L a Bosch S5 Battery 100 (74Ah) was ordered with the reg number. It lasts for weeks if the cars not used I highly doubt it's a problem with the battery.
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Might also be aux belt tensioner pulley :-\
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Might also be aux belt tensioner pulley :-\
The aux belt tensioner and pulley is approx 9 months old, aux belt 3 months or so. GM parts.
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Might also be aux belt tensioner pulley :-\
The aux belt tensioner and pulley is approx 9 months old, aux belt 3 months or so. GM parts.
Have you checked the pulley ::)
Initial increase in load could also be the aircon kicking in, which would add a significant load to the belt/tensioner :y
Also see Kevins starting/charging diagnosis guide...
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Might also be aux belt tensioner pulley :-\
The aux belt tensioner and pulley is approx 9 months old, aux belt 3 months or so. GM parts.
Have you checked the pulley ::)
Initial increase in load could also be the aircon kicking in, which would add a significant load to the belt/tensioner :y
Also see Kevins starting/charging diagnosis guide...
The tensioner is the last in the loop before the belt gets back to the crank pulley so it won't be subjected to the extra load - the a/c compressor, power steering and water pump will be though.
Might be worth checking that the belt is the correct length - when it is put under load it will wedge itself more deeply into the grooves in the pulleys - if the tensioner doesn't take up the slack then a loose belt can make some very odd noises.
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The belt would have been from VX with the Reg number, Apart from this I couldn't say which type of belt I have fitted tbh. If the numbers are still present on the belt i'll make a note and post on here :y
It's only when the car is under load there's an odd sound around 4,500rpm and above it becomes notable or when driving if you kickdown... But if everything is off and you rev/Kickdown again it sounds normal no odd noises.
Only real reason why I believe it may be the alternator as I heard a very similar (but louder) sound just before the alternator went 2 years ago resulting in the engine becoming very erratic and the battery light/symbol on the dash to light up... I was planning on changing the alternator for a new one next year regardless anyway (in summer naturally), the refurbishment was more of a temporary fix albeit a long term one as at the time the car needed more urgent/costly repairs due to only owning it some 1-2 months at the time.
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There were two slightly different lengths in common use on the V6 - the reason being that some alternators had a slightly different diameter pulley.
For piece of mind I would check that the tensioner was in the middle of it's range of movement.
I would also get a 15mm socket and a breaker bar and quickly slip the belt off so that I could turn/spin each of the pulleys (A/C, power steering, water pump, alternator & tensioner pulley) to check for rough running.
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Assuming the Aux Belt is ok, my first choice would be the Aux Belt Tensioner pulley, 2nd choice would be Water Pump Pulley loose or water pump on its way out, 3rd Alternator.
When the AB Tensioner Pulley goes they tend to go quickly from the centre spindle outwards.
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Water pump was changed for a new GM one same time as the aux/cam belt etc some 3 months ago.
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Start by following Kevin Woods guide :y