Samsung RSH1DBMH (fan?) Noise Problem please!

I have a Samsung RSH1DBMH which is just under 3 years old (Jul 07) and has recently begun making a loud noise similar to an overworked fan coming from the top of the fridge at the back. The noise stops when I open the frridge door and re-starts after several minutes. It has become progressively louder in the last few days.

I unscrewed the rear assembly at the base of the fridge last week and gave it a proper clean by removing a build up of dust which apopeared to temporarily clear the problem however the noise has now returned and I suspect the absence of noise was due to it having been switched off for a good while whilst I cleaned/defrosted it.

Anyway, it sounds like a fan or equivalent but wish to know if it’s something I can fix or will require an engineer to visit..? (Nothwithstanding the challenges of Internet diagnosis!)

Thanks