Well, that fix didn’t take long to fail; they sure don’t make ’em like they used to:
The “new” fan’s bearing failure sounded more like an owl than a dog, but it was certainly not what we wanted to hear in the middle of the night. A replacement fan costs on the order of $60, which seems like an absurdly high number for what’s basically a clock motor, a plastic fan blade, and some stamped steel.
After mulling the situation for a bit, I concluded that the refrigerator has reached that age where stuffing more money into it doesn’t make much sense: the compressor will drop dead in fairly short order. It’s time for a gonzo fix that also slightly reduces the clutter in the Basement Laboratory Warehouse: stick a PC case fan and wall wart into the freezer, ignore their temperature ratings, and see what happens.
A polycarbonate sheet, a band saw, some step drills, a big hole saw, and an hour of Quality Shop Time produced a perfectly serviceable space transformer to mate the fan to the airflow director:
The plate surrounds the squishy foam washers from the OEM motor mount, with the fan on its own rubbery posts: there won’t be any vibration transmitted to the plastic air flow director! The obligatory Kapton tape on the right holds a closed-cell foam wrap around the wires to prevent rattling; I’d done much the same when I tore the thing apart after the first OEM fan failure.
The air flow is toward you out of the screen: the fan draws air from the refrigerator compartment through the evaporator coils, then directly into a square duct that leads back to the refrigerator. Whatever doesn’t make it into the duct flows into the freezer compartment through the row of vents at the top of the picture.
I assume some serious modeling went into choosing the OEM fan blade configuration and spacing so as to optimize the distribution. I hope just moving some air in roughly the right direction will suffice; I have no way to measure any interesting numbers, so this is entirely cut-and-try.
The PC case fan expects 12 VDC, which comes from a standard wall wart conspicuously labeled “For Indoor Use Only”. Well, this is certainly indoor, even if it’s not quite what they expected. The wart plugs into a cobbled-together extension cord receptacle with male 1/4 inch quick-disconnect tabs that match the female QD connectors on the OEM wiring harness that originally plugged into the fan:
All that fits into the space behind the rear panel, with the wart wrapped in a sheet of closed-cell foam to prevent rattling and provide a bit of protection:
The rear panel covers the mess, exposing only the row of vent holes along the top. The air flow is upward through the evaporator coil and fins, through the fan, and back to the two compartments.
One question remains: will the fan continue to start below 0 °F (-20 °C)?
Given the ball bearings in the fan, it ought to remain quiet, but I’ve thought that before. Now, however, I have a generous supply of case fans and wall warts that plug into the mechanical and power adapters, so I can replace fans for a long time.
The Smell of Molten Projects in the Morning 
I became enlightened IE switched to an oil free compressor from a vacuum cleaner when cleaning the back of a refrigerator. It really blows dust away and its hellraiserish noise (96 dB) guarantees there is nobody interfering me. The procedure applies to desktop PCs, set top boxes, etc. .
“Robot Lessons”
By Ed Nisley, August 01, 2003
“Moving lots of high-speed air requires a noisy motor and a line cord; any rationally sized battery just won’t suffice.”
It’s astonishing how much fuzz builds up on the condenser coils located just over the floor under the refrigerator. You’d think the designers would make those things easy to clean, but … noooo!
Nice hack. Love it. There’s a reason there are 3 boxes of PC fans stored in the attic….. they often come handy.
Not sure that the compressor will fail soon, as you say. Refrigerators and freezers just keep on working, in my experience – even if it means running 24/7/365, 100% of the time, to maintain temperature….
About 3 years ago I replaced my fridge and freezer, as the freezer was running nearly continuously, using 2.4 kWh/day. Replacing it reduced that to 500 Wh/day….. It paid for itself in 16 months. The refrigerator paid for itself in 13 months (!) in the reduced electricity bill. I added some extra insulation to the refrigerator to lower energy consumption even more, by another 25%: https://picasaweb.google.com/motorconversion/RefrigeratorInsulation
If your fridge or freezer are old I wouldn’t wait too long replacing them with newer ones. This is one case where it can make very good economic sense to throw away (or Craigslist?) your old fridge/freezer even though it’s still working perfectly fine and replace it with a new one.
Replacing the fridge, freezer and getting a laptop instead of desktop reduced my electricity bill by about 55% (10.5 kWh/day went down to 5 kWh/day – most of it consumed by the hotwater boiler). Soon after, the electricity company sent someone around to check what was going on…. they were worried I might have messed with the meter :-)
That would likely happen with this one; I should dig out the Kill-a-Watt meter and perform some science on it.
As you’ve seen, all of our white box appliances are having troubles. This afternoon’s entertainment will be tearing the dryer apart again; fixing the wire noise revealed an annoying sheet-metal buzz that’s got to go.
Drat!
Speaking of White Goods, aren’t we about due for my annual prodding you about the rest of that damned washing machine story? :)
Some traditions should not be messed with. [grin]
OK, I’ll write it up…
“they were worried I might have messed with the meter :-)”
“FBI: Smart Meter Hacks Likely to Spread”
http://krebsonsecurity.com/2012/04/fbi-smart-meter-hacks-likely-to-spread/