Whirlpool American Fridge/freezer problem

Whirlpool S20BRSB21 18.9CF purchased March 2005

Thankfully only had one problem since we bought this fridge/freezer in 2005 but now have concerning problem and any help welcome before l consider calling for service help.
Recently had loud clicking noise from behind the appliance, this lasts for about 5 mins approx 3 times a day, if we open either door of fridge or freezer it stops but starts again immediately we close the door. We also have occasionally when using the water dispenser, spluttering, this also happens about 3 times a day but not always at the same time of the clicking noise. Any ideas or help welcome.
We have pulled the appliance out of its position & thoroughly cleaned all parts.