Thanks for the reply

I've looked at them all to be honest and can see nothing obvious. I have wondered if everything is true when new but it's wear in the tensioner from it working that causes the problem in the first place?

Now you remind me tho there is a crack round the thread for the fan, not that it affects the pulley, I keep meaning to have a go at changing it but can't spare the vehicle long enough to strip it and the fans off and in the boot now anyway

Thanks

Towsey