This tensioner pulley needs replacing right? (video)

[g3org3y]

Initially car noted to have a chirping noise at the front. Took to the mechanic few days back, of course the noise disappeared completely and they could not recreate. Apparently all ok.

Regardless of that, it looks to me that the belt over the tensioner pulley is not running smoothly. Quite notable movement.

Here's a video I took:
https://vimeo.com/441132673

I will insist on this being replaced along with the idle pulley and a new belt. What do you guys think?

Have advised wife not to drive the car until it's sorted.

[bearman68]

Appears fine to me.

Some vibration and jumpiness on the belt is expected due to torque changes acting on the belt.

[g3org3y]

Thanks, that's interesting. None of my other cars (including 2 with the same engine) have this level of movement of belt on that pulley.

To my ignorant eye, doesn't seem 100% correct. Perhaps I'm overthinking in the context of the recent chirping noises?

This video is similar and suggests a problem though:
https://www.youtube.com/watch?v=rPRxObxYc0k

Edited by g3org3y on Friday 24th July 05:29

[bearman68]

Bear in mind it is more difficult to see in a video, but that's my view.
The belt chirping can be a pile of not very nice things. On my D5 it turned out to be a) a failing A/C compressor, b) a failing overrunning alternator pulley, and finally c) a failed tensioner (presumably as a result of everything else.
Expensive

Best of luck

[g3org3y]

Thanks. No harm in changing I suppose.

[oakdale]

It's not easy to diagnose from a short clip on the internet but that sounds and looks very much like a faulty alternator pulley to me.

They usually have a freewheel directional clutch to prevent the belt from flapping about at idle when the angular speed of the crankshaft varies during each revolution, the bearing within the clutch will probably be seized or partially seized.

Is it a PSA vehicle?

[g3org3y]

oakdale said:

It's not easy to diagnose from a short clip on the internet but that sounds and looks very much like a faulty alternator pulley to me.

They usually have a freewheel directional clutch to prevent the belt from flapping about at idle when the angular speed of the crankshaft varies during each revolution, the bearing within the clutch will probably be seized or partially seized.

Is it a PSA vehicle?

No, BMW N52 6 cylinder engine (3.0).

I've booked in to have the serpentine belt, idler pulley and tensioner done. We'll see how it goes. Will update.

[brman]

I am going to guess the opposite to bearman. I think you are right, there is too much wobble on the belt on that idler pulley and it probably has shot bearings.

[stevieturbo]

g3org3y said:

Thanks. No harm in changing I suppose.

As long as the work is done by a competent person and with quality parts, there is no harm in changing.

[oakdale]

g3org3y said:

No, BMW N52 6 cylinder engine (3.0).

I've booked in to have the serpentine belt, idler pulley and tensioner done. We'll see how it goes. Will update.

Sorry for suggesting it was PSA .


It's easy enough to check it if you can get your hand to the end of the pulley, remove the belt and twist the pulley back and forth quickly against the mass of the rotor and you should find it freewheels in one direction if it's ok.

[g3org3y]

Got the tensioner + pulley + belt replaced. Car sounds better to me now and no belt wobble anymore.

Edited by g3org3y on Saturday 8th August 09:33