Oil pump chain ?

I have a 2008 plate trafic 2ltr dci

It has started making a rattle noise I

Changed timing chain but noticed

Tonight a rattle still there a loud one

Stripped it back down and noticed

Oil pump chain very loose to the point

I can push it up against engine casing

I am hoping this is the cause !

But I am looking to find out if they

Can be adjusted or do I need to

Buy a new chain ? Can any body shed

Some lite on this for me ! Feeling

Frustrated ***128545;