advice?

I have a Samsung srs 2028 side by side fridge freezer. The temp on the fridge has risen and it has started to make that loud 'whirring' noise, which ceases with a clunk upon opening the fridge door!
The freezer is fine.
I have had the fridge about 10 years and have had this problem before about 5 years ago, an engineer came round and changed the pump or whatever the fix is for this (seemingly common problem, judging by internet forums etc!). Of course I do not really want to spend another £150 for the same problem.
Any advice would be appreciated.
Many thanks
Mark

mark
August 2011