Buzzing noise after engine off

[MCGlasgow]

All you good people out there...

I have recently aquired an 07 Leon tdi (the slow one) and I can hear a short buzzing (maybe whirring) sound once I turn the engine off. Initially I thought it might be normal but the wifes Altea (with the same engine although less miles) does not do it. I wouldn't say it was that loud a sound and does not seem like something is definitely broke but I am in the "just bought a second hand car and paranoid about every noise" phase.

In case it makes a difference, I noticed over the last couple of days that the length of time that the noise goes on for seems to be variable. The first bunch of times it was only for 2 or 3 seconds, but in the morning yesterday and today it went on for much longer - like 15-20 seconds. It sounded like after 2 or 3 seconds there was dip in the volume like something was about to stop but then it picked up and carried on again. If it does it again for long enough, I will try and get the bonnet up and see if I can locate it.

Does anyone have any idea what this might be? Theoretically the car still has some warranty from the dealer (although not SEAT) that I bought it from so there is an opportunity to get it fixed assuming it is a definite fault - but I am sure this won't be straightforward, it never is.

I don't like going into dealers unprepared so any help would be appreciated.
Also, if there is a possiblity that I could fix it myself I would be intereseted.
Cheers,
Martin

 

[sssstew]

have you managed to locate where it is coming from yet?

 

[MCGlasgow]

Possibly - it did for long enough this morning that I could get a quick look. It seems to be coming from the back centre or back right of the engine (looking from the front). There is a black box there with a bunch of cables going in that might be the culprit - when I put my finger on it the buzzing noise seemed to be slightly damped. Can you identify this part or suggest an alternative cause from this area?

It seems based on only minimal data that it buzzes for longer if the car has not warmed up much. It only buzzed for about 2 seconds last night but I had been driving for a while.

Cheers.

 

[goonerjs]

We had a thread on this a while back as mine does the same intermittently. Concensus was that the EGR valve was to blame and this was perfectly normal. This it was possibly techie that confirmed though I could be wrong.

 

[MCGlasgow]

Cheers for this - I had a quick look at the other thread and it does sound similar. Although mine does it pretty much every time. Do you know what the black box is?

 

[MJ]

The noise is probably origionating from part of the vacuum control system, most of the soledoids are located in that particular area on the baulkhead.

 

[conkerman]

My wifes Toledo has made odd noises like you describe since new. I had it down to Air-con (my Exeo makes a right din) or vacuum lines.

I also sometimes get a stange 'twangy' noise bit like a ruler on a desk. Never worried about it tbh

Conks

 

[MCGlasgow]

The noise is probably origionating from part of the vacuum control system, most of the soledoids are located in that particular area on the baulkhead.

MJ, do you think this is anything to worry about?

 

[MJ]

Just more of an annoyence than anything else to be honest mate but if it's under some kind of warrenty I'd take full advantage of it an see if you can get them replaced.

 

[MCGlasgow]

From a fairly random google search at lunchtime I think the black box is called a "solenoid valve block" the VW part number for AZV/BKC/BKD/BXE engines looks to be: 6Q0 906 625.

Although I am by no means 100% sure of this informaton - just though I would share in case it was any use to anyone and so that I can claim my lunch break was not entirely wasted.