Strange noise.

**willo** · 7th Nov 2006, 19:40

Hi all,

As some of the members here are mechanics I have a question for them (if possible of course), when switching off the engine of my Td4 MY01 I regularly hear a kind of spinningdown noise which I took on video and can be heard when going to the link below. I narrowed it down as probably being caused by the fact my EGR-valve is put out of service. (Last week I put it to work again and didn't hear that noise during that whole week). My question now is, what can cause this kind of noise pse? Is it indeed EGR related ? (Mine disconnected for years already, my neighbour who owns a Td4 Sport of 2005, also with EGR blocked, has the same spindown noise as I noticed it last week when he came to see me).
Thanks for possible answers and take care.

http://www.youtube.com/watch?v=C9a_FGlvpag

**TEMPL4R** · 7th Nov 2006, 20:10

I haven't come across it yet, Willo. I'm sure if it made that noise, our customers would be racing back to us.

We'll have to do some investigating.

Chris

**willo** · 7th Nov 2006, 21:05

Originally Posted by TEMPL4R

I haven't come across it yet, Willo. I'm sure if it made that noise, our customers would be racing back to us.

We'll have to do some investigating.

Chris

Hi Chris,

But the funny thing is that under normal circumstances, I mean sitting in the car when the engine is stopped and with the hood etc. closed it is hardly to hear from the inside. (In fact i was very surprised myself as well that it wounds that hard with the hood open and the camera pointed towards the engine). So it struck my attention when my neighbourg stopped his car at my place and I heard it that I remembered having heard a similar noise at certain occasions in the past, when I stopped the engine and came out of the car rather quickly. I made another video as how it sounds when sitting in the car. Will add it to this post straight after I entered this text. (Otherwise I loose it all.....

)
I think the noise comes from down at the back of the engine but not sure of course.

Here it is:

http://www.youtube.com/watch?v=su6TyusSE28

**freelanderPX54** · 7th Nov 2006, 21:43

It could be the fan that blows air into the vehicle, mine makes a noise like that if the fan has been on fast.

**petefletcher** · 8th Nov 2006, 10:27

Does the TD4 have an oil centrifuge like the TD5?
If it does then that's what you're hearing.

**willo** · 8th Nov 2006, 18:54

Originally Posted by freelanderPX54

It could be the fan that blows air into the vehicle, mine makes a noise like that if the fan has been on fast.

No, my fan always on 1. Besides the noise comes from the outside (motorcompartment).

**willo** · 8th Nov 2006, 18:55

Originally Posted by petefletcher

Does the TD4 have an oil centrifuge like the TD5?
If it does then that's what you're hearing.

Don't know but shouldn't the noise be there then all the time ? It doesn't show up all the time, most of the time but not all the time??

**Bob R** · 10th Nov 2006, 20:56

Originally Posted by willo

Don't know but shouldn't the noise be there then all the time ? It doesn't show up all the time, most of the time but not all the time??

Hi Will

I don't think the EGR system is the culprit. I think you will find that the noise is being generated by the cooling fan in the ECU Environmental Housing (large black L shaped box between the battery and the bulkhead). This only operates when the under bonnet temperature is high enough for the sensor in the housing to call for it to be on (which would explain why you don't always hear the noise) but if energised it then continues to operate for 7-8 secs after turning off the ignition.

To see if this is in fact the cause you can try this simple test. There are two corrugated soft rubber hoses connected to the ECU housing towards the back of the engine bay. The one furthest from the windscreen is the air supply from inside the cabin to the ECU cooling fan. Make sure the annoying noise is happening then sqeeze that hose briefly. You should hear the noise level change as the fan intake is restricted. To be absolutely sure, take the cover off the ECU housing and disconnect the supply plug to the fan (see pic), turn on the ignition, then turn it off again and there should be no noise.

Regards Bob

**Noel Johnson** · 12th Nov 2006, 07:32

Originally Posted by willo

No, my fan always on 1. Besides the noise comes from the outside (motorcompartment).

Hi Willo,

I think FreelanderPX54 meant the radiator cooling fan, not the internal cabin fan.

I couldn't really hear anything on the vid although mine does "whine down" if the cooling fan has been on after I turn the engine off.

HTH

Noel.

**willo** · 12th Nov 2006, 19:00

Originally Posted by Bob R

Hi Will

I don't think the EGR system is the culprit. I think you will find that the noise is being generated by the cooling fan in the ECU Environmental Housing (large black L shaped box between the battery and the bulkhead). This only operates when the under bonnet temperature is high enough for the sensor in the housing to call for it to be on (which would explain why you don't always hear the noise) but if energised it then continues to operate for 7-8 secs after turning off the ignition.

To see if this is in fact the cause you can try this simple test. There are two corrugated soft rubber hoses connected to the ECU housing towards the back of the engine bay. The one furthest from the windscreen is the air supply from inside the cabin to the ECU cooling fan. Make sure the annoying noise is happening then sqeeze that hose briefly. You should hear the noise level change as the fan intake is restricted. To be absolutely sure, take the cover off the ECU housing and disconnect the supply plug to the fan (see pic), turn on the ignition, then turn it off again and there should be no noise.

Regards Bob

Hi Bob,

Thanks for the advice but that ECU fan is not the culprit, when that is spinning down I can hear a soft zooming noise in the cabin, not at all the ticking sound I caught on video ??

**willo** · 12th Nov 2006, 19:03

Originally Posted by Noel Johnson

Hi Willo,

I think FreelanderPX54 meant the radiator cooling fan, not the internal cabin fan.

I couldn't really hear anything on the vid although mine does "whine down" if the cooling fan has been on after I turn the engine off.

HTH

Noel.

Hi Noel,

Are you sure you listened to the 1st one (in the opening post of this thread) or are you sure your soundcard is working ok

?? On the 2nd one you can indeed hear nothing as that's the way you can hear the noise when the hood is closed and still sitting in the cabin, in the 1st post the noise is taken with the hood open and the camera pointed roughly towards the source of the noise which seems to come from below and behind the engine, from under the airfilter box or so ??

**Noel Johnson** · 13th Nov 2006, 13:04

Ah sorry, silly me looked at the second one. I'll have another listen tonight when I'm at home

**Noel Johnson** · 13th Nov 2006, 20:37

Hi,
Just listened to the first vid - duration is about the same as the fan wind down on mine but as I've never heard it with the bonnet open I can't comment any further - sorry.

**Bob R** · 13th Nov 2006, 22:05

Originally Posted by willo

Hi Bob,

Thanks for the advice but that ECU fan is not the culprit, when that is spinning down I can hear a soft zooming noise in the cabin, not at all the ticking sound I caught on video ??

Oh well never mind but I am still intrigued and it is a strange coincidence that the noise lasts for the same time as it takes for the ECU fan to be shut down. With my ear to my ECU housing, I can hear a much fainter version of your noise and it stops if I unplug the ECU fan.

Have you thought about relay chatter? They can buzz and as the battery voltage drops off after turning off the ignition the frequency would probably change as per the sound in your recording.

Best regards

Bob

**willo** · 14th Nov 2006, 19:04

Originally Posted by Bob R

Oh well never mind but I am still intrigued and it is a strange coincidence that the noise lasts for the same time as it takes for the ECU fan to be shut down. With my ear to my ECU housing, I can hear a much fainter version of your noise and it stops if I unplug the ECU fan.

Have you thought about relay chatter? They can buzz and as the battery voltage drops off after turning off the ignition the frequency would probably change as per the sound in your recording.

Best regards

Bob

Hi Bob,

What intrigues me is the fact that during the week I had the EGR operational again I didn't have that noise ????