LG Microwave Fan Motor Replacement — Three Different Fans, Three Different Problems
LG microwaves contain up to three separate fan motors, each serving a different purpose. Replacing the wrong fan wastes money and leaves the original problem unsolved. Understanding which fan does what helps you diagnose the issue before ordering parts.
The Three Fans in LG Microwaves
Exhaust/ventilation fan (over-the-range models only): Pulls smoke and steam from the cooktop below through a filter and vents it outside or recirculates it. This is the large, noisy fan activated by the Vent High/Low button. Countertop microwaves do not have this fan.
Stirrer fan (inside the cooking cavity): A small fan or rotating metal blade at the top of the cooking cavity that distributes microwave energy evenly. Some LG models use a rotating antenna instead of a stirrer fan. When the stirrer motor fails, food heats unevenly — hot spots and cold spots.
Cooling fan (magnetron/electronics): Blows air across the magnetron and control board to prevent overheating. This fan runs during cooking and for a few minutes after the cycle ends. When it fails, the magnetron overheats and the thermal cutoff shuts down the microwave mid-cycle.
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Symptoms by Fan
| Symptom | Fan Type | Part |
|---|---|---|
| No ventilation from range hood | Exhaust fan motor | 5209W1A009A ($30-$90) |
| Food heats unevenly despite turntable working | Stirrer fan/antenna motor | EAU62005001 ($15-$45) |
| Microwave shuts off mid-cycle, works again after cooling | Cooling fan motor | 6549W1S017A ($20-$60) |
| Loud grinding from above the cooking cavity | Exhaust or stirrer fan bearing failure | Varies |
| Fan runs but airflow is weak | Grease-clogged filter (not the fan) | Clean or replace filter |
Exhaust Fan Diagnosis
Before replacing the exhaust fan motor, check the grease filter. LG over-the-range microwaves have a mesh or charcoal filter on the bottom that catches cooking grease. A clogged filter restricts airflow dramatically, making the fan seem weak when it is actually running fine. Remove the filter and run the fan — if airflow is strong, clean or replace the filter ($10-$25).
If the fan does not spin at all despite the motor humming, the fan blade may be jammed with grease buildup or the motor bearings have seized.
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Cooling Fan — The Hidden Critical Component
The cooling fan is the most important fan you cannot see. It runs during and after cooking to keep the magnetron within its operating temperature. When this fan fails, the magnetron overheats within minutes and the thermal cutoff shuts the microwave down. The unit works again after cooling (30-60 minutes), making the problem seem intermittent.
This fan is inside the cabinet and requires removing the outer cover to access — which means dealing with the high-voltage capacitor. Professional replacement is recommended.
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Tools Required
- Phillips #2 — for cabinet and mounting screws
- Insulated screwdriver — for capacitor discharge (professional only)
- Nut driver 5/16 inch — for fan motor mounting nuts on some models
The Real Cost of DIY
Average DIY attempt: $150-400 in tools you may use once, plus the risk of further damage. Our diagnostic visit costs $0 — we find the problem and give you an honest quote.
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Replacement Procedures
Exhaust fan: On over-the-range models, the fan motor is accessible from inside the cabinet after removing the outer cover. Disconnect the motor wire connector, remove the mounting screws, slide the motor and fan blade assembly out. Transfer the fan blade to the new motor if not included.
Stirrer fan/antenna: Access from the top of the cooking cavity. Remove the stirrer cover (usually a snap-fit or single screw). The motor mounts above the cover with a wire connector.
Cooling fan: Inside the cabinet near the magnetron. Requires cabinet removal and capacitor discharge. Professional repair recommended.
Frequently Asked Questions
My LG over-the-range microwave fan is weak. Is the motor dying?
Check the grease filter first — a clogged filter is the most common cause of weak ventilation. Remove and clean the filter (or replace it). If airflow is still weak with the filter removed, the motor may be failing.
My LG microwave works for a few minutes then shuts off. What is wrong?
The cooling fan that keeps the magnetron from overheating has likely failed. The magnetron overheats, the thermal cutoff shuts it down, and it works again after cooling. This requires cabinet access and capacitor discharge — professional repair recommended.
Can I replace the LG microwave fan myself?
The exhaust fan on over-the-range models can be accessed without opening the high-voltage section on some models. Stirrer fans are accessible from the cooking cavity. The cooling fan requires opening the cabinet near the high-voltage capacitor — hire a professional.
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