What you will find is the fridge evaporator has blocked up with to much ice and the noise you hear is the fan hitting the ice.
For this you have 2 choices either turn the appliance off and leave the fridge door open for 24 hours and this will allow the ice to melt.
Or empty the fridge and from there remove the water bottle at the bottom at the back (if fitted).
Then remove the screws at the bottom of the rear panel.
Then remove the vent covers on the back and there will be a screw in there each side. Now these may be iced up so you will need to clear the ice.
Then remove the center panel going up the back wall in the fridge were the lights are.
Now you can pull the back panel off. It will be iced up so may be a bit difficult but it will come.
Once removed use a hairdryer to defrost the evaporator and then melt the ice around the fan.
Once clear refit the panels and retry the appliance and this should cure the fault. But if it does it again then theres a defrost issue with it. Either the heater, thermal cut out or sensor which you would need to test with a multi meter to see if faulty.
But from what you say and the noise this will be a blocked evaporator inside the fridge section causing this and doing the defrost will cure it.
Hi, thanks for your advice, I tried removing the panels at the back of the fridge however I only managed to loosen the bottom one but it wouldn't fully come off. I will try defrosting it at the weekend. I'm not sure the bottom of the panel is as flush as it was, would that matter? It's as tight as I could get it, I think I disturbed some of the ice behind it. The fridge is working fine now.
Ok no worries when you can defrost it and that should cure it.
Don't worry about the panel not being flush. It will be because of the ice behind there but that wont cause the problem.
Messing with the rear panel has probberly moved some ice from the fan so that's why it gone ok now. But just becarefull as im afraid until its been defrost it will do it again. Hopefully it will last until weekend for you.