Garage Door Symptom Diagnoser
Tap what your door is doing. Get the likely cause, the danger level, and an honest DIY-or-pro call — before anyone tries to sell you anything.
Most likely cause
Broken torsion spring — the bang was it letting go. Look at the shaft above the door: a broken spring shows an obvious 1–2 inch gap in the coils.
Why it's dangerous
The spring carries the door's full weight (often 150–300 lbs). Without it, the opener strains, cables can whip loose, and a manually-lifted door can free-fall. Don't disconnect the opener and lift it by hand.
What it should cost
Spring replacement typically runs $250–$600 for a pair installed — run the estimator for your door's specifics.
Most likely causes, in order
- Broken spring — opener force-limits trip because the door is suddenly heavy (check for the coil gap first)
- Frayed or slipped cable on one side
- Bent track or seized rollers binding the door
DIY check that's safe
Visual only: inspect the spring for a gap and cables for fraying from the ground. If either looks wrong, it's a pro call — springs and cables are the two do-not-touch components.
What it should cost
Springs $250–$600 (pair) · cables $90–$200 · track work $150–$350. Estimate yours →
Most likely cause
Safety sensors (photo-eyes) — the two little lenses near the floor on each side. Blocked, dirty, sun-blinded, or knocked out of alignment. This is the #1 "repair" homeowners get charged for that costs nothing.
Fix it yourself, in order
- Clear anything in the beam path (leaves, cords, cobwebs)
- Wipe both lenses with a soft cloth
- Gently bend brackets until BOTH sensor LEDs glow steady (not blinking)
- Check the wires up to the opener for staple damage
If that fails
A sensor service call runs $50–$150. Anyone quoting hundreds for "won't close" without checking sensors first is telling you something about them, not your door.
Most likely causes
- Broken spring making the door too heavy (check for the coil gap — if broken, PRO)
- Stripped opener drive gear — very common on older chain units; the motor spins, nothing moves
- Trolley disengaged — someone pulled the red release cord (easy DIY: re-engage per your opener manual)
What it should cost
Re-engaging the trolley: free. Gear kit repair: often under $150 with service call. Opener replacement: $220–$550 installed. Estimate yours →
What's happening
One side has lost support — a rolled-out roller, snapped cable, or bent track. The door's weight is no longer evenly carried, and forcing it can drop it out of the opening entirely.
Do this
Don't cycle it again, keep cars and kids clear, and call a pro. Realignment typically runs $150–$350; damaged cables or track sections add to it.
Most likely causes
- Dry rollers, hinges, and springs (the usual)
- Worn steel rollers — nylon rollers are the quiet upgrade
- Loose hardware rattling in the tracks
DIY that's safe and works
Garage-door-specific lubricant (not WD-40) on rollers, hinges, and the spring coil surface; snug visible bolts on hinges and brackets. Ten minutes, twice a year.
If it's still loud
Tune-up with a roller set typically runs $80–$250. Grinding that survives lube can be a failing bearing plate — worth a pro look before it becomes a spring job.