odd sound when engine is switched off

[indymorg]

hi i have got a 06 octy 19td 120000 miles on now when the engine is switched off it almost sounds like it moose like a cow it is heard inside when its quiet.any one any ideas please

[disbloke]

Could just be the cars radiator or aircon winding down.

[Aspman]

My VRS used to squeak/beep when it was turned off.

When away on it's own and I never figured out what it was.

At a guess there is a gas seal somewhere letting in air as the engine cools making the noise, but that's a guess.

[starkj73]

The Exhaust Gas Recirculation (EGR) valve makes a noise when the engine stops.

Can't say it sounds like a cow.

[El Dingo]

Not sure about the Octavia, or the 1.9 td... some cars have a pump in the cooling system that runs after the engine has been switched off. These pumps circulate water around the engine and/or turbo to prevent hot spots and run for some minutes. The pumps can get very noisy prior to failure.

This is just an idea - I don't know if Octavias are even fitted with such a pump.

Edit - http://briskoda.net/forums/topic/167150-coolant-pump-b/

Edited 22 September, 2011 by El Dingo

[Nick_H]

Have you made sure the Mrs is out of the car ? Mine spends most of the time moaning about something or other but I've found her moaning especially bad if I lock her in the car ....

[shahoc]

I was going to post the same, my 1.9tdi makes a noise after turning the engine off. Sounds like some kind of pump priming itself. Can anyone shed any light? I heard its something to do with a cooling fan, but the sound makes me think its something else.....

[Phil-E]

My Seat does this.

It's a fairly deep noise on mine. Like a low pitched whoosh.

I'm guessing it's just turbo/exhaust/intake or other gassess settling down.

It does it whether cold or hot etc.

Phil

[Stormchaser]

My 1.9tdi does this also.When i lift the bonnet to trace the noise its the cooler fans winding down.Done it since it was new (2006) now 46K.

[indymorg]

the sound only lasts for about 3 seconds. is there an actuation lever or somthing that works in some way when engine stops.if so maybe it needs lube or on the way out. when first heard noise it only lasted for about 1 second

[El Dingo]

the sound only lasts for about 3 seconds. is there an actuation lever or somthing that works in some way when engine stops.if so maybe it needs lube or on the way out. when first heard noise it only lasted for about 1 second

Then it's not the secondary cooling pump at least...

[classic]

My 1.9 tdi elegance was making a very similar noise. It turned out to be the flap that moves in the ventilation/heater/climate control unit, to control fresh or recirculated air. I only noticed it after reversing onto my drive or into a parking space then turning the engine off. A mechanic friend looked at it, removed the pollen filter and sprayed some silicon spray down its throat. No more moaning noise. It turns out that these cars go into recirculated air mode automatically when you select reverse gear to keep exhaust fumes out of the cabin.

[muntus]

It's none of these things in my '08 Elegance - The noise comes out of a unit high up off-centre right at at the back of the engine compartment (just under the wiper valance panel). You can feel it vibrating when you have someone else turn the engine off and it DOES sound just like on of those cow-mowing tube-like toys young children enjoy. It has six soft (i.e. low pressure) rubber pipes about 8mm in diameter that lead to the unit from various points throughout the airflow path from the air intake to just before injection. I believe it monitors or relieves the vaccuum in the air flow. It may also be associated with the Air mass flow meter as the wire from that latter unit passes into the wiring loom from it.

[FriendlyFire]

There is an anti-shudder valve inline with the EGR. It has a butterfly valve which opperates for three seconds on switch off. The valve is powered by an electrical motor. It's purpose is to cut off the air going into the engine after the "ignition" is switched off. Stops the diesel running on.

It makes a particular sound. Mostly you will hear it after it releases rather than when it opperates first since the engine noise masks it.

[Stormchaser]

Its the EGR valve.Quite normal.

[marcuscorvanius]

Did you ever sort this?

 

I noticed on mine the other day that as driving along the noise I can only describe as a squeel / schreech happens intermittntly.

 

I does not matter if i am under load or cruising or driving slow the noise seems constant but intermittent will go load then back to a low pitch squeel / screech again

 

When i then park up the noise is constant. I sound from the alternator at first which I swapped to no joy, belts all look in good nick and no player in any of the bearings. I don't however think it is mechanical because when i shut the engine off it chirps quite loudly for a few seconds and slowly gets quieter until all that is left is a loud hiss which again gets quieter and quieter

 

I have also check the water pump by taking the coolant tank cap off and leaving it running. Apparently that is a good way to diagnose a bad water pump. I am now completely at a loss at what it could be.

 

I see much talk about the EGR valve and also a turbo valve. Any ideas are welcome

 

cheers

[indymorg]

no i never bothered to do anything about it. so long that it wasn't serious i just learned to ignor it, its onlywhen i swtch off