03 2.0 HDI Transmission whine - happytorque
I have a C5 2.0 HDI with a slight transmission whine at certain speeds. It is most noticable between 35mph and 50 mph in 4th gear on a steady throttle. If you accelerate hard or take your foot off the gas, the noise all but dissappears. Also at about 70mph in 5th when taking your foot off the gas, the noise is heard for about 3 seconds, then it subsides. Any ideas what might be the problem? My citroen dealer has been "unable to hear it" for over year now and so the problem remains, even though the car is just two years old and still under warranty. Cheers, Trev

Edited by Webmaster on 10/10/2009 at 00:19

Citroen C5 2.0 HDI Transmission whine - none
Could be the Diff. Going back to my apprentice days of the 60's we were taught that a diff will wear and become noisy at the speed at which the vehicle is usually driven, and at multiples of that speed. For example, a car normally driven at 30mph might develope a diff whine at that speed, it would also whine at 60mph and 90mph but be quiet at speeds in between.
Citroen C5 2.0 HDI Transmission whine - Aprilia
Sounds very much like the diff to me. The whine is at the crownwheel/pinion teeth contact frequency and they are usually most prominent at 50-60mph on a light throttle. Only cure is a transmission rebuild (which may be the reason the garage can't hear it....).
Citroen C5 2.0 HDI Transmission whine - Dr. Kipperlips
I think my 03 Registered C5 2.0 HDi 51k miles is doing the same, in every gear around 2-2500 revs a loud howling whining noise can be heard, but only when the speed is held steady - lifting off or speeding up stops the noise altogether. Citroen have replaced the turbo to no avail and now think its an electro valve fault (going back in tomorrow).
I've noticed that this fault only occurs when the engine is warmed up, and is especially apparent in the scenario when you drive until the engine is warm, then turn off for a few minutes (eg stopping at m'way services), then continue on. Bought second-hand from Citroen approved dealer so have warranty, but only 3 months left :-/
Did you ever get yours sorted, or can anyone offer anything further or is this different from what you were experiencing?
Citroen C5 2.0 HDI Transmission whine - happytorque
Well Dr Kipperlips, i never got it sorted.
Mine is also a 2003 2.0HDI and has done 49K.
Im with Aprilia....i reckon its the diff. You can play a tune with the throttle pedal.
Mine only does it badly when hot....and the 'worse after a short stop' scenario that you describe is also true of mine too. Thats one bit i just dont understand. Why would sitting for 15 minutes, then setting off again make any difference? Perhaps Aprilia can offer a suggestion on that one?
I first noticed mine getting noisy at 6,000 miles. Its got no worse in the last 3 years, so it might be nothing to worry about.
Citroen C5 2.0 HDI Transmission whine - Aprilia
Heat soak from the engine into the transmission?

Its not unusual on some cars with 'notchy' gearboxes to feel much better after a short stop. Heat soaks into the gearbox and thins the oil, making the gears shift easier. When the car is driven from cold the airflow over the transmission case means that the transmission takes much longer to warm up.
Citroen C5 2.0 HDI Transmission whine - happytorque
Yes that would explian it. In fact i cant think of any other reason. Might be worth trying a thicker grade of gearbox oil? Or would that be a bad move?
Citroen C5 2.0 HDI Transmission whine - Aprilia
I very much doubt it would make any difference.
Citroen C5 2.0 HDI Transmission whine - Dr. Kipperlips
I have a bit of light at what may prove to be a dead-end tunnel:

Citroen UK have come back to my garage with 'Replace all the plastic fuel hoses with rubber ones'. Garage has said that they're not prepared to start replacing clip-in plastic pipes with jubilee clips and rubber hose. The mechanic says "When he worked for Peugeot" that the HDi engine used in the early 307 and 406 models had a similar issue where a whine appeared to come from right behind the dashboard. The fault with those was a resonating sound from the fuel return valve/pipes. The Pug fix for this was to replace part of the fuel pipe with a dampener system which cured "50% of the cars it was fitted to". I'm interested in giving this a go, but not if its gonna cost me a fortune for a 50-50 fix even if the part is still available and fits the Citroen HDi engine.
I guess there's a chance it'll fit due to Citroen and Peugeot sharing so many parts?

Has anyone ever heard of this / tried it / think it'll work?

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