The summary a technician would give
On a Criterion dryer the sound is the diagnosis. A rhythmic thump is a flat spot on a roller, a continuous squeal is the idler pulley, a rattle that changes with the load is something loose in the drum seam, and a scrape is the drum contacting its bulkhead. The order below is what does the work on this page.
What you observe
- A rhythmic thump that keeps time with the drum — A flat spot on a support roller, which comes round once per revolution and gets louder as the machine warms. A result here decides whether the next two checks are worth doing at all.
- A clatter that stops when the drum is empty — Coins, buttons and zips find their way past the seal and then rattle round the blower housing. Mention it when you book a visit; it changes which parts a technician brings.
- A deep hum with no drum movement — The belt has broken, so the motor turns and nothing else does. Repeat it once if the answer is ambiguous rather than moving on with a maybe.
- NEAR MISS: the noise comes with a burning smell — Stop the machine. Noise with a smell is a lint and heat problem rather than a worn bearing, and it is urgent. Rule it in or out before moving on, because the next check assumes an answer to this one.
Ranked causes for this machine
- Worn drum support rollers — Ranked first because they carry the whole weight of a loaded drum and wear flat rather than failing suddenly, which produces the thump owners describe.
- A dry or failing idler pulley — Second because it spins continuously under belt tension with no lubrication of its own, so it squeals long before it seizes. Nothing below this line is worth chasing until this one is ruled out.
- A frayed or broken drive belt — A fraying belt slaps as it passes the idler; a broken one leaves the motor humming with a stationary drum.
- A blower wheel that has loosened on its shaft — It rattles under airflow and can shear entirely, which is why a rattle that changes with the fan speed is worth chasing. It belongs in the order here because the check for it is cheap and the answer is unambiguous.
The order that saves time
- Press down on the drum front and listen again — If the scrape changes, the front glides or the felt seal are worn, which is a different repair from the rollers. Confirming it costs less than assuming it, which is why it is worth the few minutes.
- Check whether the noise stops when the drum stops — Noise that continues briefly after the drum halts is in the blower rather than the drive. If the answer is clear, stop here and act on it.
- Rock the cabinet to see whether it sits level — A machine with one foot off the floor amplifies every sound it makes. Eliminate it properly before moving down; a half-checked cause comes back later.
Owner-side procedure
- Empty the drum and check the seal edge for coins — Run a finger round the front seal with the power off; small hard objects live there and end up in the blower. It is the sort of check a technician does first, for the same reason.
Tools: torchAbout 15 min
- Clean the lint filter and its housing — A choked filter makes the blower work harder and noisier, and it is the first thing to eliminate. Take a photograph before you disturb anything you will have to reassemble.
Tools: vacuumAbout 10 min
- Listen with the machine running and the cabinet unloaded — Note whether the sound is at the front, the rear or underneath; that alone shortens a technician visit. It takes less time than reading about it.
About 10 min
- The last owner step is the one above this line — Everything beyond here belongs to somebody with a meter and the habit of using it properly.
What to turn off before you start
Safety
Isolate the machine at the plug or the breaker before you open it. Some components hold energy after isolation, which is why service manuals say to wait. The terminal block behind the rear panel carries the heavy current and is not a place for a curious hand. The switches that sense the door stay exactly as they are.
The line between a fix and a call
Put the boundary here: you own the outside of the machine and the lint path; the drive train belongs to a technician. It is not about difficulty; it is about what happens when something goes wrong. Call the same day if the breaker trips when the machine runs, or if the cabinet gives you a tingle when you touch it.
Other pages at this level
Scope of this page
This page is written for the Criterion dryer as a class rather than for one family or model line.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
