funny rattle...

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FlySpeck
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funny rattle...

Post by FlySpeck »

Hi lads, I noticed today that when the turbo goes on boost, 2k to 3k, I hear a kind of rattley noise, not like mechanical / valves etc, but more like running a thin stick along a railing.....or one of those things you put on yer bike spokes in the 70's....lol

After the revs pass 3k, the rattle disappears!

Any ideas guys?
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steve_earwig
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Re: funny rattle...

Post by steve_earwig »

3,200 rpm by any chance?

The worry is usually the crank pulley but it could just be noisy injectors :(
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DiscoPol
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Re: funny rattle...

Post by DiscoPol »

steve_earwig wrote:3,200 rpm by any chance?

The worry is usually the crank pulley but it could just be noisy injectors :(
what is the worry with the crank pulley steve? mine does exactly the same and disappears at 3,200 rpm

i thought it was the 3 rd piston or something or other on the HP fuel pump kicking in that made the noise go, i was really hoping it was anyway and not pulleys and belt related stuff :(
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Re: funny rattle...

Post by steve_earwig »

That's what I reckon but I'm just being cautious, I don't want to just assume it's one thing when there's a small chance it could be something else that could conceivably take out the engine. I could have just said "oh, don't worry, they all do that when they're got a few miles on them/been fed too much sub-standard fuel" and risk the chance of feeling a right see you next Tuesday when his engine went bang 'cos I didn't mention the pulley.

(Paint a line across the pulley, take it for a drive and check the line didn't break up)
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DiscoPol
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Re: funny rattle...

Post by DiscoPol »

Cheers Steve, will get the "tippexski" out later and have a crack at it,

its bloody raining here at the moment so it might have to wait, I thought I had left the wet stuff behind in manchester but it seems to have followed me.
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Re: funny rattle...

Post by FlySpeck »

3200 sounds about right. So is there a problem with the crank pulley breaking up?

Or does it spin on the shaft or something? I would have assumed the engine was belt timed and so I guess that the problem must be cracking of the pulley...?

Must take a look, could be a noisy injector or a pump noise, must read up more on the hdi motor!
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Re: funny rattle...

Post by steve_earwig »

It's two parts bonded with rubber, the rubber perishes and the outer can spin against the inner. Eventually it fails, drops the aux belt which can (and has) ended up inside the cam covers and take the cam belt off...

The usual thing is to change it along with the cam/aux belts, idlers etc. when you do a cam belt change. Trouble is not many people that don't know do this. Hey, it's bad enough splashing out for a water pump to replace one which is probably ok :(
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FlySpeck
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Re: funny rattle...

Post by FlySpeck »

cheers for the info steve, top stuff mate.

I would rather do the parts now than wait till it comes off, so thats a job for the end of the month then if nothing goes wrong before it, plus I have no idea when or if the TB was ever done so thats a must anyway.
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Re: funny rattle...

Post by steve_earwig »

Yours is probably the injectors if it goes at 3.2. Changing the timing belt is a good idea, especially if you don't know the history of the car.
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lofty
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Re: funny rattle...

Post by lofty »

All HDi's come with an amount of "HDi noise paranoia" :lol:

Everyone ive had had made different sorts of noises, unless its the obvious disintergrating bottom pulley rattle, most are accepted as normal these days.

My current 90 is quieter than my last 110, more because the DMF aint on the way out
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FlySpeck
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Re: funny rattle...

Post by FlySpeck »

there is a definate light rattle, does sound like a pulley (youtube lol) and does disappear completely after 3k....if its injectors then is that a sign of inj cleaning required on the hdi?

also it doesnt do it until 2k plus, when boost begins.

not the pulley then we reckon?
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FlySpeck
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Re: funny rattle...

Post by FlySpeck »

ok, I had a chance to really pay attention to the noise tonight, it only does it while accelerating in gear (or under load), and disappears completely at exactly 3200 rpm....and if you knock the box into neutral, and rev the engine, no rattle.

And its more of a chatter, like a fast ticking sound - so in respect of what someone said earlier about the injectors & 3200 rpm - whats the issue there? I think it is injection related from the rpms via the helpful post by steve.
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Re: funny rattle...

Post by steve_earwig »

Mine sounds kind of like the tappets need doing, except they're hydraulic :?

So... Louder if I floor it, builds up from just over idle until 3,200 then drops down much quieter, almost inaudible over the din of the rest of the car. If I've got the throttle to the floor and am a bit slow coming off it to change gear the rattle carries on a little louder for a few tenths of a second. It used to only happen when the car was totally stone cold but it's gradually getting worse, I used to only be able to hear it inside the car but now it's loud under the bonnet too, I put a screwdriver to my ear and went round under the bonnet and it's definitely louder on #2 (I think it was) injector. If they were as cheap as chips I'd have changed them to put my mind at rest but they're not :( Apparently even if the injectors are reconned the bit that rattles isn't.
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BruceT
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Re: funny rattle...

Post by BruceT »

Sounds exactly like the wagon we have with 150k on it.

It also has a knackered crankshaft pulley which is getting replaced next month.

Again, im not saying im right but im pretty sure its injector rattle or the 3rd piston not kicking in till 3200rpm exactly due to wear and tear.


It only does it usually when you use more than 50-60% throttle, ie booting it, gently accelerating it doesnt do it.
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FlySpeck
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Re: funny rattle...

Post by FlySpeck »

yeah I concur with all of that, mine is exactly the same but not that noisy as yet. I have searched in evilbay and found used injectors from £20, so even though its a gamble, there may be only one required, or there may be a fix for a while in swapping them around till it shuts up.

it seems that the pre-injection cycle for mid range is from 2200 too 3200 rpm, and so when the extra pressure piston comes into play on the injection pump, thats when the injectors rattle. The ecu switches off PI at 3200 rpm, hence the noise goes away.

I wonder if injector magic would work? Its epic on a petrol car.

Or is there a way to disable pre-injection?
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