On Alfa number 15
AO Platinum Member
Join Date: Dec 2005
Location: United Kingdom
It is dead easy.
The new tensioner will come with a pin locking it in the untensioned state.
Jack up the car then remove the driver side wheel, and the lower cover in the wheelarch
Then Simply unbolt the old one (single bolt) and remove it from under the belt.
Bolt on the new one, thread the belt over it in the correct direction then pull out the pin on the tensioner with some pliers.
It will then spring against the belt and take up the tension.
It is a good idea to renew the 2 fixed tensioners and the belt at the same time if you can afford to do it all.
You will never be cool driving a Vauxhall.