C5 Intermittent Loud Whine

[Citroen Newbie]

Hello!
We are complete beginners when it comes to Citroens, although my father had many including BX's, Safari's and some I couldn't name but I remember their hydralic suspension system well as it seemed to include 2 big chains and a couple of drilled cannon balls!

Last summer we brought a 2003 C5 Hdi with 150K Miles after our Volvo V40 bit the dust. Seriously impressed and happy bunnies

The car had been regularly serviced by an independent but there were no books to prove but stickers and chalk marker with dates on the car.

Recently the car has been off the road with a fault that was difficult to diagnose by our local garage. It wouldn't start so knowing that it had been sitting for several months before we purchased it we changed the battery. It wouldn't start even with the new battery. The Tech in our local garage thought it needed a new key and eventually after having the car for weeks trying this and that had to take the car to Main Dealers for reprogramming and then diagnosed the alternator required replacing!

Fixed and back on the road and loving it we now have a new problem. A very loud, high pitched whine/ scream which is intermittent and does not occur in idle. It doesn't sound like metal on metal.

There is no loss of power. In fact once you get to 55/60 mph in 5th it clears. It doesn't always happen, sometimes it starts and runs fine with no noise until you get to around 30 mph when it starts. Sometimes it only kicks in when you start to slow down and sometimes its louder than others.

Considering the trouble our local garage diagnosing the problems last time we were just wondering has anyone any ideas what this could be??

The Tech has muttered something about the Turbo sticking and 'cleaning out the blades' as a way of fixing the problem. Is this possible?

Any advice would be gratefully received.

[Paul-R]

Can you isolate where the scream is coming from, at least roughly? One thought I have is that the one-way clutch on the alternator pulley is beginning to seize. Others may have some suggestions.

[Citroen Newbie]

It appears to be coming from the back of the engine towards the bulkhead but its really difficult to tell.

[Hell Razor5543]

Well, first, welcome to the Forum. Great atmosphere here, and people do want to help. Second, it might help to record the sound and post it up on the forum so that anybody who has experienced such an issue can help. I don't know how to post videos myself, but somebody who does will probably advise you soon.

[Paul-R]

Indeed. Where are my manners? Welcome to the forum.

[Citroen Newbie]

Thank you for the welcome!

Hope this is the start of a long rewarding friendship

[Paul-R]

If the noise is at the rear of the engine it's probably not the alternator as that's low down at the front.

Some more questions:
Is the noise present in more than one gear? i.e. if you change from 3rd to 4th (or whatever) is it still there?
If it is still there does the pitch change in line with the engine speed or stay the same as the road speed?
If not either of the above does the pitch stay the same regardless of road or engine speed? - when it's there that is.

[Citroen Newbie]

The noise doesn't change note just how loud it is the faster you go the louder it gets!. But as said before it stops at around 55-60 mph but not necessarily when you put it into any particular gear, changing from 4th to 5th doesn't always stop it but the speed does.
The first thought was that the clutch wasn't disengaging properly as it doesn't happen in idle but when you start to speed up. The more pressure on the power and the faster you go the louder the noise until it shuts off. Once it's gone it seems to come back when you start to slow down to around 45 mph even if you just take your foot off the gas and don't change gear or brake

The noise appears to be coming from behind the engine by the bulkhead on the driver's side (we think!)

[dnsey]

Just thinking aloud - if it's not road speed related, but varies with load, it sounds rather like an induction / exhaust issue. EGR, perhaps, going by the apparent location?

[GiveMeABreak]

Well, first, welcome to the Forum. Great atmosphere here, and people do want to help. Second, it might help to record the sound and post it up on the forum so that anybody who has experienced such an issue can help. I don't know how to post videos myself, but somebody who does will probably advise you soon.

As the noise is difficult to describe considering it could be a pulley / belt or at worst turbo, it may help if we could actually hear the noise. If you can use your phone to record the noise (most have a voice recorder), save the file to your PC and email it, I'll probably be able to convert it and link to it so members can hear exactly what the sound is. It could be very helpful to hear it. I've sent you a Private Message with an email in for you to send it to me.

[Citroen Newbie]

Thanks for all the suggestions.
Hubby decided to take the car to local Tech yesterday PM incase it's the turbo. Last thing we want is a kaput engine! Son is heading for Uni in September and we need our big beastie for the 1000 mile round trip
If the Tech can't sort it out fast (and I have my doubts on past experience) I will record the sound and send it to you as soon as I can.

[Peter.N.]

Does it still do it if you push the clutch out or put it in neutral?

And yes, Welcome to the forum.

Peter

[ekjdm14]

the fact that it seems to come back when you slow down/let off the accelerator suggests to me that it's not turbo related. As the pitch is constant but volume increases with speed until it vanishes, I'd suggest looking for loose plastics/heat shields etc under the car, even just a broken clip here or missing bolt there. Reason I say this is it's similar to the noise I've had from air rushing past a cracked undertray before now and that used to vanish over a certain speed...

Definitely would be good to have a video or at least audio recording to listen to though as sounds are one of the trickier things to diagnose at "arms length"

also, welcome from us too

[Paul-R]

the fact that it seems to come back when you slow down/let off the accelerator suggests to me that it's not turbo related. As the pitch is constant but volume increases with speed until it vanishes, I'd suggest looking for loose plastics/heat shields etc under the car, even just a broken clip here or missing bolt there. Reason I say this is it's similar to the noise I've had from air rushing past a cracked undertray before now and that used to vanish over a certain speed...

My thoughts were going along that line as well. Something that has a resonant frequency that is activated by air going past it. I would have thought that the sound would be a mid range tone or drone rather than a higher pitched shreek though.

[RichardW]

Check for a warm wheel after a run - a similar noise on our C4 was a sticking rear brake. Front brakes sticking on C5s is not exactly unknown!