Noise on idle e90 320i

[Dillon]

the e90 has 30k miles on it and is an auto.

There is a faint noise on idle (disappears when driving) that can only be heard if you turn the radio off and listen for it,

It's a little shudder / rattle that sounds like it's coming from the upper left hand side of the engine bay. It's also not constant there's a 1-2 second gap between each sound.

Revs do not change and idle perfectly, car drives perfectly also.

Is there some kind of pump in that area that could be getting noisy at that mileage? Or is it more likely that it's just something loose hitting off something? Engine mounts also spring to Mind but on 30k they couldn't be gone?

No warning lights, service due light is on since I bought it (5 days ago) and it's been booked in for Saturday week since the day I bought it.

Anyone ever had this before?

[Andy]

Is your fan on?


Regards,

Andy

[Dillon]

Yes it would probably be in time with the fan as if you start from dead cold it takes about 30secs for the noise to start happening - but I didn't think you'd hear that through the firewall? Sounds very close to the firewall from inside the cabin

[Andy]

Turn off the air fan and see if it disappears. If so that's your culprit, they can get noisy and squeaky and can be heard from the cabin. Easy fix if it is.




Regards,

Andy

[Dillon]

Oh you mean the air fan for the cabin? No it stays when that is off sorry, I thought you meant the radiator fan

[John_D]

It's hardly the a/c ventilation motors in the dash? In the E46 they are quiet but in later cars I've driven such as my wife's passat them can sound a bit odd and constantly making little adjustments.

[Dillon]

No it's definetly engine bay, you can hear it with the hood up aswell - I'll try and get a video done later on might clear things up

[Don B]

Hardly a timing chain problem at such low mileage? Saying that though, a family members 07 320i
with 45k miles needed the chain replaced

[Dillon]

Better not be haha - timing chain wouldn't be a spaced out noise though would it? Would be continuous and remain while driving?

[Dillon]

This describes it perfectly so fingers crossed this is the culprit