M42 noise

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wrcarter
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Fri Apr 15, 2011 9:51 am

My M42 suddenly started to make the strange 'tractor' or diesel engine sound generally assoicated with the timing chain. However this noise is only produced below 2500 rpm. From reading other posts about this topic the noise seems to appear around 3000 - 3500 rpm. Is there something else it could be? Has the tensioner just failed or should I just go and replace the chain and assoiated parts? Thanks in advance
Duke137
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Fri Apr 15, 2011 10:01 am

Mine is tappety at idle and right through especially when cold. It could be any of the following:

1. Slack timing chain just need to replce tensioner
2. Slack Timing chain, could do with new and guide rails
3. Exhaust manifold (cylinder 1) blowing which sounds v.similar to chain
4. Rattly valve gear and lifters, old high mileage cars now

I would change the oil first see what happens as it makes a difference to mine, I change the oil every 6 months MAX.

Change the tensioner as a matter of course, and if it still rattles just live with it mate that is what the M42 does there isn't many that don't.

Oh and mine runs sweet other than the noise and I had chain and guide rails done a little over a year ago which made no difference tbh and is more likely worn out valve gear as I am showing 156K (if that is even correct, who cares lol)
How do you pronounce 'either'? I say 'either', but some say 'either'. Either is correct.
320iAN
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Fri Apr 15, 2011 10:02 am

whats the mileage?
ive seen others post with the similar noise you are describing who have been lucky enough that by replacing the tensioner with a newer item for a E36 318iS have quietened the chain rattle down.
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wrcarter
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Fri Apr 15, 2011 1:41 pm

Thanks. There is 158k miles on it so is probably due anyway. Head was replaced at 128k by the previous owner but don't know if the timing gear was replaced also. Manifold seems fine. Might order a tensioner and see how that goes.
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wrcarter
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Sun Apr 17, 2011 9:58 am

Found a small leak on the exhaust manifold at cylinder 1. The is a spare e36 m42 manifold here so going to try and swap them. Does anyone know if it will definitely fit? Looks like it should. I ordered a tensioner too so will replace that after the manifold. If it is not solved then will start taking apart the rocker cover and timing cases and see if I can find what's wrong. Just don't like driving it if something major is gone. Any tips on removing the manifold bolts?
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