The short answer
When a Criterion dishwasher starts making a new noise, open it mid-cycle and look at what is loaded before assuming a part has failed. Most noise in this appliance is loading rather than mechanics. Nothing below asks you to open anything that should stay closed.
The observables
- A rhythmic knocking during the wash — A spray arm striking a tall item or a handle protruding through the basket. It is the sort of check a technician does first, for the same reason.
- A grinding that comes and goes — Something hard circulating in the sump, picked up and dropped by the wash pump. Photograph it if you can, because it is the sort of detail that is hard to describe later.
- A buzz only at the end of the cycle — The drain pump working against an obstruction rather than moving water freely. It is the sort of check a technician does first, for the same reason.
- A rattle from the door or the kickplate — Panels and trims work loose over time, and they buzz in sympathy with the pump. Mention it when you book a visit; it changes which parts a technician brings.
Causes, most likely first
- Loading that fouls the spray arms — First because it is the commonest cause and the easiest to confirm: an arm that cannot turn freely knocks once per revolution. Mention it when you book a visit; it changes which parts a technician brings.
- Debris in the sump or the wash pump — Second because glass fragments, fruit stones and bones all get past the filter and then circulate noisily. Confirming it costs less than assuming it, which is why it is worth the few minutes.
- Loose panels, trims or the kickplate — Nothing has failed; a loose panel simply resonates with the pump and sounds far worse than it is. That single observation eliminates more of the list than any amount of guessing.
- A failing wash pump bearing — Last, because it is genuinely uncommon and everything above it makes a similar noise for far less money. The rank is a starting point, not a verdict; what you observe outranks it.
Check in this order, and why
- Open the door mid-cycle and look for a fouled arm — Turn each arm by hand and watch what it touches; the answer is usually obvious within seconds. It sits above the more dramatic explanations because it is the one you are statistically likelier to have.
- Take the filter out and check the sump — Look for glass, stones and bone fragments, all of which circulate and grind. If the answer is clear, stop here and act on it.
- Run the machine empty and listen — An empty machine that is quiet has a loading problem rather than a mechanical one. The position matters more than the name: work the order rather than the one you have heard of.
The homeowner checks
- Reload so nothing blocks the spray arms — Spin each arm by hand after loading; if it touches anything, move the item rather than hoping. Do this before the check below it, because the answer changes what that one means.
About 15 min
- Remove and clean the filter and the sump — Lift the filter out, rinse it, and wipe the sump with a cloth, checking for fragments around the impeller. It is worth doing properly once rather than quickly twice.
Tools: cloth, glovesAbout 20 min
- Run an empty rinse programme and listen to each phase — It separates wash noise from drain noise cleanly, which is exactly what a technician wants to know. It needs nothing you do not already own.
About 25 min
- Go no further than this without test gear — What is left is diagnosis rather than inspection, and diagnosis needs instruments.
Power, water and hands
Safety
Switch off and unplug before a single fastener comes out. Stored charge does not drain the instant the supply stops. Bail out a flooded tub with a jug rather than tipping the machine, which puts the load on the door hinge. Leave the door or lid switch wired exactly as you found it; it is a guard and not an inconvenience.
The line between a fix and a call
Draw the line here: you own everything inside the tub; a technician owns everything under it. That line is about tools and access rather than about confidence. Bring somebody in if the tub will not empty at all, because a standing tub grows a smell within a couple of days.
Other pages at this level
Scope of this page
Scope note: this page addresses the dishwasher as a class of machine under the Criterion badge.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
