this vehicle has only covered 37000 miles.
customer conplained of knocking noise from the engine but only when hot.
we had a look and the knocking seems to come from the cambelt area, we took off the belt cover and it seems to be one of the variable cam pulleys knocking on start up and when hot. we have replaced the engine oil and put in a forte treatment and this shut it up for a week also but now the noise is back. it looks like the pulley is knocking on it stop? has anyone else had this problem?

This is a known problem on some of this engines.
If the vehicle has FSH then fight for goodwill.

You will probably find that the owner has not had it serviced as it should have been because of the "low miles" HTH

regards Mark