Whirlpool ET18DKXZN00 Evaporator Fan Issues

[Sonic Purity]

Whirlpool Designer Style (top freezer)
Model: ET18DKXZN00
s/n: EB1630766
Type: 18TFA92
mfg. 04-92

Evaporator fan motor has been getting progressively noisier for years, but still runs (98% of the time).

 

New Motor Issue

Waded through the Chinese junk on Amazon this past November and found and purchased a new Whirlpool genuine FSP 482731 MOTOR-EVAP. Motor made in U.S.A. (yay!): Bay Motor Products, Traverse City, Michigan. UL. Date of manufacture 050521. Fan blade is also made in U.S.A. and identical to the original other than a few nubs on the new one which would not affect operation.

With the back inner freezer panel removed, the original fan spins Clockwise (looking straight at it from the front of the refrigerator).

Bench tested the new fan: runs Counterclockwise. Blade is identical to the original: they did not switch the direction/angle of the blades.

These are 120VAC shaded pole motors, so no way to reverse other than maybe disassembling and flipping the frame around, at which point the terminals are on the wrong side, requiring harness extension and possibly dealing with clearance issues.

No note in the box about any sort of production change.

Question 1: Does the direction of air flow on an evaporator fan matter?

 

Original Motor Lubrication Issue

Not knowing whether the air flow direction mattered and assuming it did, i returned the 482731. The original part number W2154419ZP motor bearing surfaces (and the rest of the motor) looked good—indeed it looks like a nicer, better built part, with a larger frame and coil. General Instruments AF4 29420-66, date code 92xx (could not read the week numbers, hence the x es).

Disassembled the motor. Cleaned the bearing surfaces with Fedron®, my go-to aggressive petroleum-based solvent, discovered during my former home audio repair career and successfully used on numerous motors in turntables and tape decks, including shaded-pole motors quite similar to this evaporator fan motor.

Re-lubed with Tri-Flow oil with Teflon®, figuring a thin oil would be good in this application, and with Tri-Flow being rated for use down to -53°C, able to work in ongoing freezing temperatures.

That repair lasted from mid-November until 19 March (a day over a week ago as i type this). The evap fan had again been getting a little noisier in preceding weeks, then all of a sudden SQUEEEEEEEEEEEEEEEEE!: metal-on-metal high-pitched squealing: lubrication fail!

Spent nearly a day in-depth researching the optimal lubricant for evaporator fan motors living in freezer sections (including here on Appliantology.org): no clear answer. When i asked Perplexity.ai the question: What is the correct lubricant for the shaft of an evaporator fan motor in a freezer? it answered:

The correct lubricant for the shaft of an evaporator fan motor in a freezer depends on the type of bearing:
    1.    For ball bearings: Use a light bearing grease. Clean out the old lubricant with solvent first, then pack with the new grease.
For sleeve bearings (also called oilite bearings): Use oil with a viscosity in the SAE 10 to SAE 30 weight range. Suitable options include:
    •    Sewing machine oil
    •    Turbine oil
    •    3-in-1 oil

This is a sleeve bearing motor. Had some 3-In-1 Motor Oil (blue and white can) on hand, rated SAE 20. Re-cleaned the bearing surfaces with the Fedron (allowed to fully evaporate as always), then liberally applied the 3-In-1 Motor Oil. Bench tested: fine. Put it back together: fine.

Now, a week later, the evaporator fan motor is again noisy, and is having trouble spinning up, suggesting this is another wrong lubricant for this application: too thick, at least at freezer temps.

This appears to be a good quality motor in usable condition. Seems to me it should be successfully rebuildable and continue to run reliably for many more years, with a suitable lubricant and proper refurbishing work.

Question 2: What is/are the optimal lubricant(s) for a shaded-pole sleeve bearing 120VAC evaporator fan motor which lives in freezer conditions?

I look forward to your thoughts, and to reporting back in the future with what else may not have worked, and what eventually did work (i hope!).

~ Thanks ~

[Econo Appliance]

Yes, direction of airflow on the evaporator matters. If you put the wrong direction fan in,  you will still get some level of cooling as you're still pushing air around, but it will do weird things like scoop up moisture and blow it all over the wrong places, leading to weird Frost buildups... also the fan blade can be noisy and the whole thing will be inefficient.

This style of fan is indeed reversible but if you bought the OEM in a Whirlpool box then you shouldn't have to reverse it. It's when you buy the universal replacements that you have to worry about all of that stuff.

I'm wondering if your fan has ever been replaced before? Maybe a previous technician put a backwards one in?

 

I checked my catalogs and unfortunately none of them say what direction your fan is supposed to spin

[Sonic Purity]

Thank you, Econo Appliance, for clarifying that the direction does matter, answering original post Question 1. You write that this style of fan is reversible. Is there a way to do so other than flipping the stator frame over (the only way i know), which moves the terminals out of the range of the wiring harness? When paying a price premium for the official factory service part, i don’t think i should have to mess with rebuilding the fan motor to reverse it—especially with no note about a production change.

Good point about previous replacement. In this case, no. This particular refrigerator was purchased by, or for, my grandmother in late 1992 or early 1993, after my grandfather died. My parents were handling her household upkeep, hence knew all maintenance histories. She only remained in this house until late 1994, then it was unoccupied until 1998 when i moved in. It’s only needed routine maintenance since 1998 until this noisy fan issue, which maintenance etc. i’ve handled. Spoke with my mother today, and she’s quite certain this refrigerator was never serviced between purchase and when i moved in.

Had the fan assembly out again a couple of days ago for a re-lube (details below). This original clockwise-turning motor with original blade moves air front to back: from the front of the fan (blade area) over the motor and back… in case anyone else wants or needs to know the air flow direction for this model. Very obvious feeling it, running it on a bench.

 

Lubrication Update

Review

• Original lube (unknown) lasted a couple of decades before the evaporator fan motor started getting noisy, and another decade before i took action
• Solvent cleaned then lubricated with Tri-Flow Teflon oil mid November 2024. Nice and (relatively) quiet until 19 March 2025 (about 4 months): sudden loud squealing and rough running sounds, suggesting metal-on-metal from lubrication failure
• Re-solvent cleaned then lubricated on 20 March 2025 with 3-in-1 SAE 20 electric motor oil (blue and white can). Only a day or so later, evaporator fan had trouble spinning up at the start of each refrigeration cycle, often taking a full minute or several to get going.

New Information

Lubricant Testing

Had the presence of mind to put various in-stock lubricants in the freezer and allow them to sit for a couple of days, then check their consistency. The three greases aren’t really appropriate for sleeve bearings like this, but i wanted to test them anyway.

Grease freezer resting test Results

• Valvoline Heavy Duty Cerulean High Temperature Multi-Purpose Grease VV70133 NLGI #2 Automotive Wheel Bearing & Chassis Lube GC-LB: no change (in consistency nor any other readily observable parameter)
• (LubriMatic?) Ultra Lube #11310 NLGI Grade # 1 1/2: no change
• LubriMatic Heavy Duty Multi Purpose Lithium Grease #11315 NLGI #2: felt slightly more grainy

Oil freezer resting test Results

• Tri-Flow: slightly tackier, and seemed to maybe separate a little?
• 3-in-1 SAE 20 (blue and white can) electric motor oil: slightly thicker/tackier
• 3-in-1 regular light machine oil (red, white, black can): no change

Sat. 29 March: Re-solvent cleaned the motor bearings and liberally applied the 3-in-1 regular oil. Note that this is different than what i did with the Tri-Flow back in November. For the Tri-Flow, i put in a few drops. This time for the 3-in-1, i really let the oil soak in, replenishing the bearings (especially the more accessible rear bearing) until it nearly couldn’t take any more oil.

 

Most Recent Re-Lube and Issue

Within a day, there was (and as i type this, is) a new style of failure: every cooling cycle, the evaporator fan motor runs nice and quiet. Gets gradually noisier during the course of the cycle: the usual rattling sound it’s been making for over a decade now. Gets quite loud by the end of a cooling cycle—louder than it’s been these past couple of decades (other than the SCCCRRRREEEEEEEEEEEEEEEEE! failure when the Tri-Flow failed suddenly after 4 months).

None of the other lubrication situations have had this repeating good-getting worse-bad noise pattern with each cooling cycle. It’s as though the 3-in-1 is migrating or breaking down as the motor runs, then re-forms or migrates back during rest.

Still seeking an answer for original post Question 2: What is/are the optimal lubricant(s) for a shaded-pole sleeve bearing 120VAC evaporator fan motor which lives in freezer conditions?

In the meantime, i intend to continue experimenting with lubricants and update this topic/thread/conversation, until achieving success. The refrigerator/freezer is otherwise in good shape and meets our needs, so no desire to replace. Maybe in a year or two, Whirlpool will be selling replacement evaporator fan motors with compatible blades which correctly move air front-to-back like this original, no matter which direction the motor turns.

[Econo Appliance]

This kind of motor is reversible when you buy a universal version.... when you buy the OEM with wings attached, it's supposed to work out of the box as-is.   Where did you buy the part from,  and can you show a picture of the box?   How much tape was on the box,  was it a return special, etc etc

 

What inspired you to bench test the fan motor to check the rotation?

 

I have not found any oil that works well for long term evap fan motor.   In a hail mary situation i put turbine oil but the problem is guaranteed to come back in months.