You might talk with the people who sold it to you - probably need the serial/model number of the unit - should be on a metal plate or sticker in the back. They can probably get you a new fan and possible install or advise you on how to do it. You can Google the model/serial# of the brand and find a parts manual that will ID the fan assembly#

Appreciate it!

The noise is most probably coming from the fan blade hitting something. The fact that you can make it go away by banging the door (basically shaking the fridge) tells me that you are moving the fan.

Can you fix it? Are you comfortable removing the back of the fridge, finding the fan and checking for a loose mounting bracket? Do you have the tools?

It is not likely that the bearings are shot after only four years. Your fridge should have a life expectancy of 10 to 15 years.

If you don't feel up to fixing it, having a repairman fix it should still be way cheaper than buying a new one. More sustainable too.

If it's a "clackity" sound, it may well be that the fan blade has come loose on the shaft and is hitting the wire guard. May be as simple as tightening a setscrew that secures fan to the shaft.

I repaired my furnace and my neighbor's furnace using their service.

You deposit like 19 bucks in the kitty, describe your problem, provide your model/serial number, and what steps you have already tried. An appliance/service tech specializing in your area will contact you via email, walk you through diagnosing it and recommend the fix.

You don't pay the service tech out of your kitty until you are satisfied. I think the minimum is 15 bucks and they recommend a tip of like 3 or 4 bucks. Both times I spent like 19 or 20 bucks. I even waited a couple days to pay until I acquired the part.

In my case, I'm a pretty hard-core DIYer but I never really jumped in to any appliance/electronic stuff. When you get in to these things they are really not THAT complicated. All the techs do are change out components. Knowing which component to change is the hard part.

I had an OHM meter that came in handy. Not saying you will need one.

All that said, what a pain in the ass. 4 years old? That's bullshit. My 2 year old GE is making a clunking noise in the ice maker. They really don't make 'em like they used to.