Good morning all.

On idle my 2009 Td4_e has developed a pretty loud rumble that disappears when revved, then reappears on idle. Standing at the radiator it sounds like it’s coming from the front left of the engine block or perhaps an ancilliary somewhere on that drive belt. It sounds high on the engine rather than low down, but I might be wrong.

It doesn’t appear to be any plastic coverings and nothing appears to be loose, so I am worried it might be a bearing or similar. I have for a while had a little squeaking on idle (see earlier post) which has not been fixed. Might be related?

The video shows the issue, very audible at the end of the vid after I’ve revved a little.

If anyone has experienced this or has ideas on what it might be (and the remedy) I would be most obliged to hear from them.

Many thanks!

Update. - cannot fathom how to add videos despite having done it before. Argh!

Richard.

Have you checked /replaced the alternator pulley since your previous posts regarding engine noise? If not I still think that is the culprit. If you look at the alternator belt with the engine running you should be able to see it fluttering. If it is then as previously suggested the alternator one way clutch has seized and it needs a new alternator pulley.

^^ That was my initial thoughts too. Just flip the alternator drive belt off and see if the pulley only turns the alternator in one direction. If it turns it in both directions, the pulley needs replacing. Past: FL2 TD4 HSE Auto
Evoque SD4 Dynamic Lux Auto
Present: Audi A3 S Line.

Try turning the air con off
Might be aircon clutch bearing 2008 xs
Snorkel
raised axle/gearbox breathers
Mantec tank guard
Cb radio
Blanked EGR
Sump guard
Scratches
Snolkle

Sounds like the Alternator is a likely candidate then. Thank you.

Can I play with the belt without worrying about timing etc, or does it have to go back on at exactly the same point like a timing belt?

I assume I can just loosen the tensioner by hand and release the belt without worrying about specific position?

It is considered best practise that the belt is renewed whenever it is removed, however if you are removing the belt to check the pulley then it should be ok to refit it again as long as you note the direction of rotation and refit the belt so that it runs in the same direction as it was originally. The belt should be renewed if you are fitting a new alternator pulley. The tensioner spring is extremely strong and you will need a 15mm socket and a long bar to be able to pull it back against the tension enough to get the belt slipped off. It would be wise to note down the way the belt runs round the various pulleys (or photograph it) so that you get it back on the right way.

hello Richard, not sure if you have fixed the noise but mine had similar noise on idle and it was a faulty water pump, had it replace and the noise has gone.

What make was the water pump hc1jlg ? FL2 MY10 TD4 GS traded in at 2 years
FL2 MY13 TD4 GS Current

Don't know local dealer did the job under the extended warranty, still fine up to now.