Question Funny engine noise at idle

#1
Hello peeps. I’m looking for some help. I’ve mentioned a couple of times a funny engine noise which is annoying me and I hope someone can help me diagnostically.

https://youtu.be/kjb3M0dMEoo

It is only when the engine has warmed up and is then only when the RPM drop below 1000. It happens consistently, during each gear change etc

The noise appeared to start shortly after a timing belt change and water pump replacement. The alternator was replaced about six months previously. The noise has been there consistently for 12 months.

Any suggestions about what to check and how?

Thank you.




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Birchall

Dick Chown Award 2016
#2
Is yours a Tdi?

if so remove the bonnet and move /hold steady the large turbo pipe that goes under the brake master cylinder.
Thst intake pipe has been the source of many annoying and baffling vibration type noises for me in the past.

If that stops the noise just secure the pipe in position with a tie wrap or similar.

Steve B
 
#3
It is indeed a TDI75. I’ll check the turbo pipe.

Could you hear the noise I mean? Higher pitched than normal engine tone.


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Birchall

Dick Chown Award 2016
#4
It is indeed a TDI75. I’ll check the turbo pipe.

Could you hear the noise I mean? Higher pitched than normal engine tone.


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That is a strange one.

Get youself a length of hosepipe about half a metre long or so.
Put one end to your ear and use it like a stethoscope. You should be able to pin point the source quite accurately.

Steve B
 
#5
Is this the upgrade to your wood post stethoscope?
It seemed to me that it was coming from near the timing belt housing and so on but I haven’t tried a hose yet! Will give it a go!


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Birchall

Dick Chown Award 2016
#6
Is this the upgrade to your wood post stethoscope?
It seemed to me that it was coming from near the timing belt housing and so on but I haven’t tried a hose yet! Will give it a go!


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The wood version is better for rattles and deep noises. The higher pitched sounds are easier to spot with the hose !!

;)

Steve B
 
#8
I love how you just say that ‘try disconnecting drive belt’. like it’s a super easy thing.
It looks like you take a large wrench (13mm is it) and haul the tensioner off the belt then push a 4mm? pin into the hole to stop it snapping back. I looked to see what kind of pin or wrench but it’s fairly ambiguous. What do people use? Is a drill bit okay again? Feels like a strong spring...


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