Stop
A burning smell can precede an electrical fire. Unplug the compressor immediately, let it cool, and don't use it again until the cause is found, especially if you see melting, charring, or smoke.
Symptoms
- Acrid or hot electrical smell during use
- Smell of burning rubber near the belt
- Smoke or haze visible near the motor
- Smell worsens the longer it runs
Likely causes
- CommonMotor overheating from extended use or blocked airflowWindings can give off a hot, slightly electrical smell when overworked.
- CommonSlipping drive belt generating friction heatA loose or worn belt rubbing against a pulley smells like burning rubber.
- PossibleOil leaking onto a hot pump or motor surfaceBurning oil produces a distinct acrid smoke smell.
- Less commonFailing motor winding insulationA more serious electrical fault that requires professional repair.
What to do
- Unplug the compressor immediately at the first sign of a burning smell; don't wait to see if it clears up.
- Let it cool completely before inspecting anything.
- Check the belt (if belt-driven) for glazing, looseness, or slipping marks on the pulley.
- Check for oil residue on or near the motor and pump that could be burning off on a hot surface.
- Look and feel (once cool) around the motor housing for discoloration or a melted appearance.
- Do not restart the compressor if you see any melting, charring, or exposed wiring.
- Have a qualified technician inspect the motor before using it again if the smell was electrical rather than clearly just a slipping belt.
Tools and parts
- None recommended beyond visual inspection once cooled and unplugged
Compressor drive beltSearch: “air compressor drive belt”
When to call a pro
If the smell isn't clearly explained by a slipping belt, have a technician inspect the motor windings before further use.
Safety
Stop
A burning smell can precede an electrical fire. Unplug the compressor immediately, let it cool, and don't use it again until the cause is found, especially if you see melting, charring, or smoke.