Doors are easier to diagnose by ear than by eye, and most people already have the information they need without realising it. There are three noises worth separating, they come from three different parts, and one of them will grow into a much larger bill if it is ignored. Two more sounds mean stop using the door, and those are at the end.
Place the sound before you look for the fault
Run the door once and watch whether the noise travels with the door or stays in one spot. Run it again and note whether it repeats steadily, happens once at the same height every time, or continues the whole way. Those two answers narrow it to a part before anyone touches a spanner. Recording it on a phone helps if it comes and goes, since a pattern is easier to hear on playback.
A rumble that follows the door: rollers
A low grinding rumble that moves up the opening with the door, loudest through the curve at the top of the track, is roller bearings. A roller is a small wheel on a stem with a bearing inside it, and a steel wheel with an open bearing has nothing keeping salt and grit out of the balls. The bearing rusts, the balls stop turning, and the wheel begins sliding along the channel instead of rolling. Check it by hand with the door closed. Every wheel should spin under a finger and feel smooth. One that will not turn, feels gritty, has flat patches on the tread, or wobbles on its stem is done. Ten rollers on a double door is normal and they wear out as a set.
A rhythmic squeal from one end of the shaft: a bearing
A squeal or chirp repeating once per revolution, always from the same end of the shaft above the door, is an end bearing. Its pitch rises and falls with the speed of the door, which is how you tell it apart from a motor noise, and it is normally at its worst on the first cycle of a damp morning before anything has warmed through. This is the one not to live with. The bearing is a hardened race that the shaft turns inside. Once it has seized, the shaft turns against the race and cuts a groove into itself, and a grooved shaft is a far bigger part than a bearing. Bearings and drums together run an estimated $130 to $250. Leave it a year and it becomes a shaft.
A crack at one point in the travel: a hinge
A sharp crack or clunk that happens once, at the same height on every trip, is a hinge. Hinges sit between the sections and take a bending load as the door goes round the curve into the horizontal track. Salt gets into the barrel where the pin turns, the pin seizes, and the plate flexes instead until something splits. Look at the joint level with the height where you hear it and check for a hairline crack radiating out of a barrel, a hinge that has opened up around its screws, or a screw drawn out of the panel. Hinges and brackets run an estimated $95 to $185, and a split hinge left in place is how a section starts to twist.
Why all three start early near the beach
The local cause is abrasive before it is chemical. Fine sand blows in under the door, gathers in the bottom of both channels and gets carried up by the rollers, where it works past bearing shields and into hinge barrels, mixed with whatever lubricant is there. Salt then rusts what the sand has already scratched. On the streets a short walk from The Strand, rollers that would run ten years out east can be gritty at four or five. Brushing the channels out dry several times a year genuinely slows it, and greasing a track speeds it up.
What a set of rollers costs, and what to ask for
Ten rollers fitted runs an estimated $110 to $210, and no other single job changes how a door sounds by as much. Ask for sealed nylon wheels on plated or galvanised stems. Nylon is quieter than steel, the sealed bearing keeps sand and salt out of the balls, and the plated stem is the part people forget, because a bare stem rusts inside the hinge barrel and then the wheel cannot sit straight even though it still spins. Do not oil the wheel itself and do not put anything in the channel. A drop of lubricant where the stem enters the hinge is everything a nylon roller wants from you.
The two sounds that are not maintenance
A single loud bang from an empty garage, often overnight, followed by a door that lifts a few inches and stops, is a torsion spring. A hard metallic snap with one corner of the door dropping and jamming is a lift cable. Both mean the system carrying the weight of the door has failed, and both mean pulling the release cord and leaving the door where it is instead of pressing the button again to find out. Everything else on this page will wait a fortnight. Those two will not, and neither is a job for a homeowner with a spanner, in Oceanside or anywhere else on this coast.