Help and ideas needed for rattling noise

[gatos]

Hi all. Need some help as my 1.9D started making a rattling noise again at idle. The noise first appeared last summer but stopped a few days later when the weather got colder. Couple of weeks ago, when the weather warmed up, the rattle returned!!! The noise is a lot more noticeable inside the cabin than on the engine bay

It only happens when the car is idling and it is the same when the engine is cold or warmed up. If I increase the revs ever so slightly, the noise disappears completely. Most of you (myself included) would immediately suggest the alternator pulley is on its way out. However, I completely removed the Aux belt and started the engine and the noise was still there. So I ruled out alternator, AC pump and PAS.

Any suggestions are welcome.

[The Improver]

How about the exhaust itself or heat shield and a wild guess of the fuel tank straps.

[Baffler]

Is it coming from the dashboard or the engine bay? Have you tried wedging your hand between the bottom of the windscreen and the dash to see if it stops?



BTW...your inbox is full

[gatos]

Originally Posted by The Improver

How about the exhaust itself or heat shield and a wild guess of the fuel tank straps.

Checked everything under the car and everything is as tight as possible

Originally Posted by Baffler

Is it coming from the dashboard or the engine bay? Have you tried wedging your hand between the bottom of the windscreen and the dash to see if it stops?

BTW...your inbox is full

I will try that. I am planning to remove the dashboard in two weeks anyway in order to convert my AC to Climate. So if there are any loose bits in there, I wil tighten them properly this time
When I am inside the car, it sounds as if it comes from the engine bay. When I go to the engine bay it sounds as if it is coming from everywhere...... ANd why does it only happen when the weather is warmer?

I have cleared a few messages on my inbox.

[Baffler]

Have you checked the stay bar on the underside of the subframe isn't touching against the body?

[Spike1918]

It must be due to thermal expansion of something, is it a dull / muted rattle or a metallic rattle?

[gatos]

Originally Posted by Baffler

Have you checked the stay bar on the underside of the subframe isn't touching against the body?

No. Will have a look at it.

Originally Posted by Spike1918

It must be due to thermal expansion of something, is it a dull / muted rattle or a metallic rattle?

That is what I thought, as the noise first appeared when the weather warmed up. I would say it is more of a dull / muted rattle. It sounds very similar to the noise you get when the alternator pulley fails. That is why i was going to change my alternator. Bloody odd

[Spike1918]

I`m not familier with your model but does it have an over the engine plastic / composite cover with sound proofing felt like material on it`s underside?
If it does it might be that touching down somewhere, when it`s warmer the materials used soften and those covers can sag and distort.

[gatos]

Originally Posted by Spike1918

I`m not familier with your model but does it have an over the engine plastic / composite cover with sound proofing felt like material on it`s underside?
If it does it might be that touching down somewhere, when it`s warmer the materials used soften and those covers can sag and distort.

Forgot to add that I have also removed both engine cover and engine undertray and started the engine, and noise was still there

[Baffler]

Try this tomorrow - if you lightly press and release the accelerator in quick succession is it more pronounced? It could be slack on the chain for the oil pump which is driven off the crankshaft.