C3 KFU 1.4 16v Aux Belt tensioner spring

[kingjafad]

Hello guys,
I have a C3 KFU 1.4 petrol 16v 2008 that has a very odd Aux belt tensioner.

https://www.ebay.co.uk/p/10043708904

On the car its upside down vs this picture.

Question is. How am i supposed to release the tension on the belt with this tensioner. I tried turning the 15mm nut on the pulley wheel clockwise and it just started to turn, not pull back the tension on the belt. Same anticlockwise.
It seems that the spring somehow needs to be compressed (in the picture it is wrapped with something to hold the spring compressed i guess).
Is there a technique? Or a case of putting a big CV clip/jubilee clip/tie wrap around the spring?

Any links to Youtube greatly appreciated to demonstrate....

Thanks in advance.

[kingjafad]

I discovered this is a specific tensioner for the start/stop model and yes, you guessed it, it needs a specific tool to compress the spring just to release the tension on the belt. A bit like a wiper arm puller but longer. Typical!

[kingjafad]

If anyone else finds this post in the future. I found a simple way to compress it.
Jack with a long bit of wood roughly cut on the end to the curve of the pulley (with the belt still on it).
Jacked it up and the whole engine wanted to move up but it gave enough slack on the belt to take it off.
Sketchey but it worked.