I have an integrated frost free zanussi fridge freezer, Zi 921/8 FF fridge on top freezer on bottom. About 4 weeks ago I notice the fan in the freezer was very noisy and seemed to be working overtime. I removed all the food and freezer baskets to a chest freezer I have in the garage and the fan quietened down. However, the fridge temperature seemed not cold enough. I opened the panel in the freezer (would not come away completely) and noticed a build up of ice under the metal grill part, but I don't know whether that is usual or normal. Last week, I took the fridge freezer out of its housing and left it off for 24 hours and checked that the pipe carrying away the water from the fridge was not blocked (it wasn't). Plugged it back in and it seems no better. The back of the unit was clean and there seems to be adequate ventilation (gap of 4" at back of unit). The motor seems to be much hotter than it should be and one side of the black mesh at the back quite hot to the touch. Any help, suggestions would be very useful. If I can repair rather than replace I would be very pleased.

Thank you.