dj57

Focus 2008 2.0 tdci Humming/Drone

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Hello everyone, as anyone had a humming or drone whilst driving, no noise change when changing gears or using the clutch, but increases during acceleration and decreases when easing off the accelerator. The noise is coming from the engine bay area and would hazard a guess I think its more to Passenger side but could be wrong.

I have driven along the road and took it out of gear and switched engine off for a few seconds and it is still audible.

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Sounds like diff bearings if it's definitely in the engine bay.  I'd want to make sure its not a dodgy tyre or wheel bearing on the NSF first though!

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5 hours ago, TomsFocus said:

Sounds like diff bearings if it's definitely in the engine bay.  I'd want to make sure its not a dodgy tyre or wheel bearing on the NSF first though!

 

 

7 hours ago, dj57 said:

Hello everyone, as anyone had a humming or drone whilst driving, no noise change when changing gears or using the clutch, but increases during acceleration and decreases when easing off the accelerator. The noise is coming from the engine bay area and would hazard a guess I think its more to Passenger side but could be wrong.

I have driven along the road and took it out of gear and switched engine off for a few seconds and it is still audible.

When my wheel bearing went. At first I thought it was transmission sound cos the sound travels but as it got worse the sound changed when going around circles or lane changes on the motorway.

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Had this recently on our Mk3 and it turned out to be a worn and misshapen tyre.

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Changed the Passenger side driveshaft and still the same, off on hols after weekend so will investigate more when I get back

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Tyre noise - what make and how worn are they?

It's almost unbelievable how much noise tyres can make - I recently swapped Pirellis for Good Year on a car I was selling - what a ***** racket I thought the transmission was falling off, yet there had been little or no noise before the swap over.

Try swapping the wheels around or better still different make of tyres

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I had the same make tyres all round when I got the car over a year ago they where new, I had sidewall issues on one off my back ones so changed both back ones for new nexens, ran them for about 3 weeks before the noise started and have in the last week swapped the backs (new) to the fronts. no difference with the tyres. I can take the car quicker on a roundabout and no change in noise, same turning left sharply. The noise starts once I get over 25 mph at 50 on duel carriageway the droning increases if increase speed and slows down when reducing speed. For the sake of the cost of 2 front bearings and age of car (2008) when I come back of my hols thinking of changing them to elevate them and or drivers side driveshaft. 

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David,

A while ago I posted on this very problem.

Below was how I diagnosed the cause of my whine.

ScaniaPBman.

PS. The internal hyperlink may not work.

 

Here's my answer to another forum member on this type of problem.

From what you say it does sound like a wheel bearing, but
which one? Here’s how I tracked down my suspicious whine.

First I just drove it around for a while, there was a faint
whine from the front left so I went straight in and changing the left wheel
bearing. Wrong. It made no difference.

Stung by this failure I stepped back a little and did the diagnostics properly.

To start with I purchased a mechanics stethoscope just like
this one
for a fiver. Then I put the front of the car up on two axle stands and chocked
the rear wheels with the handbrake tight as well. Then I started the engine put
it in gear and set it running at 30MPH. The wheels are off the ground but
turning at a reasonable speed so the bearings are running round.

Next from underneath I put the stethoscope on the hub
carrier as close to the bearing as possible and listened. Then the other side, and
the drive shaft support bearing (my prime candidate for the cause of the
whine). All were humming away smoothly. If there was to be a bearing failure it
would have made distinctive noise clearly noticeable with the stethoscope.

I would suggest you do the same type of test on the rear
wheels getting a friend to spin the wheel for you while you are underneath
listening carefully.

WARNING. Going under a car which is up on stands with the wheels turning for an investigation
like this is a hazardous thing to do with all those moving unguarded parts. I
did it very slowly and carefully with someone in the driving seat at the
controls. All I can say is if you are not confident don’t do it. I told you it
was dangerous!

Well where was my whine coming from? It didn’t take me long
to pin it down from under the front.

It was the left side final drive gear support bearing way
inside the gearbox. Bad news.

If you are getting your whine on corners, this technique
should help you identify the cause with confidence. A failing bearing will be
picked up like this with no cornering load or vehicle road load.

ScaniaPBman.

 

I have had a lot of satisfaction from my stethoscope. Once you get used to a 'good' bearing noise, then a failing bearing will stand out like a sore thumb. Just keep probing around underneath and you will find the source of your noise.

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1 hour ago, dj57 said:

I can take the car quicker on a roundabout and no change in noise, same turning left sharply. The noise starts once I get over 25 mph at 50 on duel carriageway the droning increases if increase speed and slows down when reducing speed

When the first of my front wheel bearings went, it took about 6 months to develop to the stage where I could really hear any noise change on cornering. Most of that time it was just that annoying droning, worst at about 50mph. The speed range where it was audible gradually widened, until eventually weaving on a wide, straight road gave a very distinct change in tone on the alternate weaves.

I used a tiny microphone strapped to various parts of the car to try to locate it, and more or less eliminated driveshaft intermediate bearing and gearbox like this. My normally silent gearbox sounded like an ancient Morris Minor spur tooth box when listened to via a microphone! A bit scary. But all the gearbox noises were extremely torque dependant, the droning was constant.

But the tyre noise was too great to really hear the droning via the mikes, until I put them inside the car, under the front footwell carpets, Then it was just about audible, but still not clear.

Eventually I located the likely suspect, replaced that bearing and it was fine, Except almost exactly 12 months later, it started again, this time developing on the other side of the weaving test, so I had to have the other front bearing done. The precision of mass production means failures can be that close, about 10 years/160,000 miles for one, and 11 years/166,000 miles for the other!

Anyway, after all that, I think my advice would be to check regularly for any bearing play, but other wise try to ignore the noise until it gets to a stage where the source becomes clear. I still have one of the bearings, there is no play or roughness at all. When spun on a lathe there is a just tiny trace of roughness if pushed sideways quite hard. The bearing would have been perfectly usable for many more miles, but for that annoying noise.

 

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Thanks for your info, as I am going to keep the car for work and considering its age I think I will change both wheel bearings, that way I know they would be ok for the rest of the cars life with me. If the noise still persists after that I will have to investigate further.

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