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Discussion Starter · #1 ·
Hi eveyone,

I hope I'm putting this thread in right place. I am trying to identify a strange rattle coming from a '96 E36 1.7 tds. The noise is engine speed related but only like once every 10 revs, if that makes sense. Is cooling fan supposed to be turning all the time when engine running?

Any response grately appreciated.
Thanks
 

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Discussion Starter · #3 ·
Thanks for the reply, on night shift so sorry for delayed response. Unfortunately not at home due to work commitments but if memory serves me right noise appeared to be from near side or front. In car it sounds like stone in tyre (but not wheel speed related) or similar to exhaust manifold gasket leak. Under bonnet sounds similar to loose heat shield on cat (but from different location) but rhythmic and definately engine speed related.
 

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If it were me I'd use a long screwdriver held against the ear and hold it against parts of the engine, the noise will transmit down the screwdriver shaft, it will get louder the nearer you get to the source.

Or buy a stethoscope :D

Let us know how you get on.
 

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Discussion Starter · #5 ·
First of all I'd like to say thanks to all who replied. Sorry about delay in response but work commitments etc but home now. Source of noise is from the fore end of rocker cover, is it some sort of pump???. Noise is like a clicking sound. When you put hand on housing you can feel it so I reckon it's contact that making noise, I hope that makes sense. Picture attached. Any help at all is much appreciated
 

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It could be your vacuum pump or even the chain tensioner gone weak/chain slapping about, if I were you I'd keep fingers crossed that doug1234 sees the thread or PM him as he is pretty clued up on diesels :thumbsup

Otherwise drop it into a independent BMW specialists and get them to confirm :)
 

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I have PM'd doug1234 a link to this thread:thumbsup

I have a spare pump from the engine I removed due to fuel pump failure.:thumbsup

I noticed there is a little piece that sits inside the pump in order to make it operate when the cam turns.
 

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Discussion Starter · #12 ·
Hi

Dunno if this makes any difference but the noise is linked to engine speed but not at same speed as engine, slower, maybe one click/rattle in every 10 revolutions of engine. Sorry if that doesn't make sense.
 

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I do not have any experience of a vacuum pump failing,if it is making noise it may be down to the fact it has reached max vacuum and then some kind of bypass kicks in similar to a power steering pump with steering on full lock ??.Might be an idea to have the engine tick over and keep tapping the brake pedal to diminish the vacuum and see if it goes quiet,this would only confirm that it it the pump making the noise.There is no way to repair these as far as I know,replacement is the only answer and they are not very cheap,I presume the brakes still have plenty of servo effect so it is still working ok.You could un tension the alternator/power steering/water pump drive belt by putting a bar (long 1/2 drive extension ) in the tensioner and pushing down,this will let you remove the belt.You could then run the engine for a minute or so and listen if the sound is still there.Not sure about timing chain noise as this would be a constant clatter and not rhythmic and the noise should reappear when the engine winds down from high revs under no load.With the belt removed,and it only needs taking off a couple of pulleys so it does not drive (remove from power steering pump should see enough slack so it will not turn,not much room to get at it on a 3 series) you have then either the vacuum pump making noise or the timing chain,removing the rocker cover cap will enable you to hear more from the timing chain area.Not sure if you unbolt the complete vacuum pump if you will get oil thrown every where with engine running without it,but it is an option. Do have a look at your drive belt when the engine is ticking over as the noise could be the tensioner itself,these although they look hydraulic in fact just have a spring in them.On my tds I fitted an after market belt that is a touch to long,when my engine is ticking over the tensioner is on full movement as it struggles to keep the belt tight,watching it when engine runs it moves in and out 3 to 4mm constantly and although there is no slipping of the belt unless I go through a large puddle in wet weather it should not really be able to move.Yours may be doing the same and could be the source of the noise in some way esp if it clatters on its stop at full travel.
 

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Discussion Starter · #14 ·
Thanks for that doug1234, I have tried using a long bar as a stethoscope to determine where noise is coming from and I am confident the vacuum pump is the source of the noise . I will try what you suggest to further establish this. I will keep thread updated.

Many thanks for your reply.
 

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Discussion Starter · #15 ·
Update,

had car to local garage to see what mechy thinks, his diagnosis is top of engine but not the front, more to back, something connected with camshaft but other than that he couldn't say, possibly sticky lifter, suggested flushing engine on next oil change if no worse by then.
Checking valve clearances might help.
Am I right in thinking that lifters are hydraulic therefore clearances not adjustable???

Regards to all.
 

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Discussion Starter · #16 ·
Update.

Removed belt and ran engine, noise still present.
Had another 3 mechs have a listen and nothing conclusive.(2 said timing chain or tensioner but noise present uprevving and down revving so I reckoned it ain't tensioner)
Took off rocker cover, nothing obvious, removed vacuum pump and if you look at pic you should see how loose pump to camshaft coupling is.
Anyone any idea where I can get one of these couplings, how best to repair it or how urgent it is to repair, judging by the wear on 2 lobes(probably not visible on pic) it been like this for a while.
I've looked at realoem and it doesn't appear on vac system diagram.

Thanks to everyone who helped.
Sorry about poor pics but hands dirty so had to get mrs with mobile to take pic.
 

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Discussion Starter · #17 ·
does anyone know if there supposed to be any spring or cushioning device between camshaft end and vacuum pump coupling. There seems to be about 10 or 15 mm play on mine which is ruining coupling and vacuum pump shaft as well as an annoying noise.

Thanks
 

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They usually have play on them, it's quite normal for them to move around a fair bit when out, there shouldn't be much twist play on them though.

If you have some spare sheet around you could try bolting it over the vacuum pump hole and running the engine with the pump off to see if it still makes the noise. It is what I'd try.
 

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Discussion Starter · #19 ·
I managed to find a plastic beaker same size as pump so filled the gap and ran engine and noise was not present. As for the play there is some twist movement which is down to wear on coupling and pump shaft where it engages coupling. (I think the technical term is "it's knackered!!!!") New pump on order from bmw dealer in inverness.

Thanks to everyone for all your help and info.:thumbsup
 

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Discussion Starter · #20 ·
Update

Fitted new vacuum pump, noise still present.
Sick as a Parrot.
Does anyone know how to verify if timing chain guide or tensioners are goosed, if fixing a big job and how much££££ ?
I can't see anything from outside offside of engine, i.e tensioners.

Help

Many thanks
 
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