Rattle from A/C compressor and pulley replacement advice needed

[Forty45]

The rattle (sounds like piece of metal tapping against the car underbody) is on a 2012 Yeti 1.2. The noise starts when the air con is turned off and engine is idling. The aircon has been recharged recently and works fine otherwise
 

The compressor is a Sanden PXE14 (part 5N0820803G). When I searched for I found the data sheet identifying different Sanden compressors, and the diagram of PXE14 refers to "no clutch" on the pulley.
 

I've read posts where the compressor clutch pulley has been identified as the source of a rattle and either a new clutch hub or complete clutch pulley has cured it. However these aren't for the "G" model compressor.

The clutch hub or complete clutch pulley for my model is not listed on eBay or Amazon etc - it's here, https://shop.acauto.pl/product-eng-49488-Clutch-Hubs-AC-5SD02-CH.html
https://shop.acauto.pl/product-eng-49654-Clutch-kit-AC-6SD10-CH.html
and more expensive than what other people have paid for the parts for their repair.

I don't want to buy a part if it might not be the cause of the noise - any views please?

If the pulley is "no clutch", can it have a rattling clutch?

Also, does anyone know how to remove this pulley? I've watched a YouTube of one being stripped on a bench, but the nuts and bolts had already been undone and it was in German. The part number can be found with many different letters at the end, but some letters are much less common despite the pulleys looking very similar.

Can the pulley be held in place with a Boa strap wrench while undoing the nut?

Is a flywheel puller needed?
 

OEM_Data_Sheets_Combined-1 (1).pdf

[Breezy_Pete]

Have you checked the 3 Torx screws that hold shear plate to pulley?

[Urrell]

1 hour ago, Forty45 said:

If the pulley is "no clutch", can it have a rattling clutch?

That type of compressor has no clutch, it rotates all the time with the swash plate angle acting on the pistons to give the flow required through the compressor.

[Forty45]

1 hour ago, Breezy_Pete said:

Have you checked the 3 Torx screws that hold shear plate to pulley?

I haven't, but just took this and they don't look loose.

[Forty45]

18 minutes ago, Urrell said:

That type of compressor has no clutch, it rotates all the time with the swash plate angle acting on the pistons to give the flow required through the compressor.

Thanks for confirming what I thought might be the case.

2 minutes ago, Forty45 said:

I haven't, but just took this and they don't look loose.

 

[Breezy_Pete]

Hold pulley still, put a tool on the central axle nut and see if there's play with attempted rotation.

[Forty45]

30 minutes ago, Breezy_Pete said:

Hold pulley still, put a tool on the central axle nut and see if there's play with attempted rotation.

Would I need the belt off when doing that?

[Breezy_Pete]

No: that should actually hold the pulley still for you 

[J.R.]

The central spline can rip out, the shear plate can be replaced and its available from Polish E-bay sellers, I have replaced mine which I damaged by recharging the aircon with the cylinder inverted at too fast a rate.

 

When I have had the hubs strip on a MK2 it made a tinkling noise like breaking glass but with the aircon on, I now have a noise like you with the aircon off, I will decribe it and why I think it could be the bearing the pulley runs on.

 

For expediency when I bought a shear plate I fitted it to an old pulley assembly which had the threaded fasteners as my pulley was rivetted, that pulley and its bearing had done a very high mileage, now I get a whuum-whuum-whuum cyclical droning noise at low engine revs with the aircon off no noise with AC on and it works perfectly, the shear plate, fixings and hub are all intact, its a noisy bearing which gets quieter when under load as it cannot then resonate, another job to be put off till its cooler.

 

The job is simple if the wheel, wheelarch liner and intermediate plastic cover is removed, access is then good, no puller needed just large circlip pliers, the central nut can be difficult to remove if the shear plate is broken and you risk bending the pump shaft, if intact its easy.

 

Use Loctite bearing fit on the splines of the drive hub, I have had a couple strip in service.

[Forty45]

8 hours ago, J.R. said:

The central spline can rip out, the shear plate can be replaced and its available from Polish E-bay sellers, I have replaced mine which I damaged by recharging the aircon with the cylinder inverted at too fast a rate.

 

When I have had the hubs strip on a MK2 it made a tinkling noise like breaking glass but with the aircon on, I now have a noise like you with the aircon off, I will decribe it and why I think it could be the bearing the pulley runs on.

 

For expediency when I bought a shear plate I fitted it to an old pulley assembly which had the threaded fasteners as my pulley was rivetted, that pulley and its bearing had done a very high mileage, now I get a whuum-whuum-whuum cyclical droning noise at low engine revs with the aircon off no noise with AC on and it works perfectly, the shear plate, fixings and hub are all intact, its a noisy bearing which gets quieter when under load as it cannot then resonate, another job to be put off till its cooler.

 

The job is simple if the wheel, wheelarch liner and intermediate plastic cover is removed, access is then good, no puller needed just large circlip pliers, the central nut can be difficult to remove if the shear plate is broken and you risk bending the pump shaft, if intact its easy.

 

Use Loctite bearing fit on the splines of the drive hub, I have had a couple strip in service.

Cheers. Mine is on 40k. The noise is like a slowish tapping of a bolt on a hollow panel on the underside of the car - as if the exhaust was knocking something. As soon as you move off it goes until you stop when it returns. It also takes a little while to start up when the engine is cold. So it doesn't sound like what you have, but once I'm able to get to the pulley area I'll report further. Is yours a PXE14 with the same part number as mine?

[Austin 7]

Hi

 

I am going to throw in an odbball suggestion for elimination purposes.

 

I once had an odd tapping noise from under the car (1.4 TSi 2012) on the passenger side, audible at idle.

 

It turned out to be the fairly rigid plastic fuel lines (flow and return) between engine and rear tank.  For the front part of their length they run inside a hollow rectangular box section.  Although Skoda fitted foam inserts in the factory, they weren't quite enough to prevent contact between the lines and the underbody.  I guess the pulsating fuel flow (which depends on revs and engine load) makes the pipes vibrate. A bit more squishy foam stuffed in and the noise was gone.

[Forty45]

1 hour ago, Austin 7 said:

Hi

 

I am going to throw in an odbball suggestion for elimination purposes.

 

I once had an odd tapping noise from under the car (1.4 TSi 2012) on the passenger side, audible at idle.

 

It turned out to be the fairly rigid plastic fuel lines (flow and return) between engine and rear tank.  For the front part of their length they run inside a hollow rectangular box section.  Although Skoda fitted foam inserts in the factory, they weren't quite enough to prevent contact between the lines and the underbody.  I guess the pulsating fuel flow (which depends on revs and engine load) makes the pipes vibrate. A bit more squishy foam stuffed in and the noise was gone.

Thanks for the suggestion. The noise is on the driver's side and sounds to be coming from the pedal box area or where the fuse box is - and I've checked in that.

[Forty45]

On 23/07/2022 at 09:10, Breezy_Pete said:

Hold pulley still, put a tool on the central axle nut and see if there's play with attempted rotation.

I've checked it and everything is tight and no play. I'll just see how it goes and if it gets worse investigate further. Leaving the a/c on isn't a problem in this weather 🌞