Help diagnosing this weird Peugeot 508 MK1 2.0 HDi whining sound

[edwrdafk]

It's especially noticeable when pressing the accelerator in 3rd gear at ~ 50km/h. When the speed is constant it is like a rolling sound, like something spinning producing this weird 'electrical' sound - listen at 1:20m.

Similar whining is present at different speeds but at different frequencies and sometimes even if i press the clutch without accelerating. Can be heard only from the inside. What could it be?

(Ignore the rattles, they are from different objects in the door storage)

[mickthemaverick]

The only thing that I can suggest, because I can't hear it all that well, is maybe clutch release bearing?

[edwrdafk]

Hmm. Well the clutch also squeaks when I press it and can be heard from outside, coming from the engine bay. That could also be the clutch release bearing. But can that bearing be responsible for this constant whining?

[mickthemaverick]

Not necessarily, if the clutch bites ok and doesn't slip you may just need to swap the release nearing.

[edwrdafk]

I don't think it's worth the amount of labor of removing the gearbox and replacing only that bearing and not the whole clutch, especially since I don't have a history of the car and I don't know when it was replaced the last time. And it would be a shame to replace only the bearing and 6 months in the future the clutch starts to go bad.

However, it still doesn't sound quite right to me. Like why is this whining only in certain gears and at certain speeds? For example, in the video it's audible in 3rd gear at 50km/h, but if I put it in 4th gear at that speed I don't hear that whining. But in 4th gear I might hear a different frequency whining at a higher speed. I'm thinking it might be something with the gearbox.

[mickthemaverick]

Applying logical thinking to your description of the times the fault occurs: as far as I am aware 3rd and 4th gears are mounted on the same shaft. If the noise occurs only in those gears it may be the shaft bearings for the drive cog when it engages at the same revs but therefore different road speeds. The loading on the bearings is from slightly different angles when the primary shaft engages with the different gear shafts so may only whine when the 3/4 shaft is engaged.
Incidentally I only suggested changng just the release bearing to keep the parts cost down assuming you were doing the job yourself and would inspect the clutch once you had the box off

[RichardW]

Perhaps something in the auxiliary drive? Does the alternator have a freewheel clutch on it?

[PaulC5]

A bit hard to see, but has the car only done 27000 km, if so I would not expect gear box bearings to be worn unless the oil level was low. When I have replaced bearings the cars had been over 160000 km and the whining noise would vary with speed, the gear and when accelerating or slowing.

[mickthemaverick]

On pausing the video I'd say that was 271466 km Paul !

[edwrdafk]

Yes, the car has over 270k kms (169k miles). I bought it 2 years ago at 250k and it had this whine then too, but I think it was less pronounced but I’m not sure. It’s my first car and thought for a while the sound is normal.

Also I don’t know if the alternator has a freewheel clutch.

I guess I have to find a good mechanic and have him hear it since it’s hard to tell from the video.

[edwrdafk]

I was looking in the engine and found this broken hose in between the auxiliary belt of the AC compressor or what is that at the bottom. Anyone knows what it is and what it does and can it be connected to my problem?

[RichardW]

That's the water drain from the fuel filter. Just hangs down, but looks like it's been caught in something.