What a noisy compact machine is telling you
Noise from a compact badge-import dishwasher is usually something loose in the tub or a machine that is not sitting square in its opening. These units are lighter and less insulated than full-size machines, so a fault that would be muffled elsewhere is clearly audible here. Empty the tub and check the feet before suspecting a pump.
What you are seeing
- A rhythmic knock in time with the spray arm turning.
- A grinding or rattling from the sump area during the wash.
- A buzz that changes when you press on the cabinet.
- The machine rocks or walks slightly during the cycle.
- A high whine during the drain step only.
- Not this fault: A hum with no water movement at all is a fill or cycle fault - read the cycle page.
- Not this fault: A noise together with water on the floor belongs on the leak page.
Most likely causes, in Dencrest order
- Spray arm striking a tall item or a handle — Why ranked: First on a small tub. Turning the arm by hand with the racks loaded finds it immediately, and it is the most common single cause.
- Hard debris in the sump or caught in the filter — Why ranked: Second: glass fragments, seeds and bone chips grind against the impeller and produce a distinctive gritty rattle during the wash.
- Machine not level or its feet not bearing on the floor — Why ranked: Third. A cabinet resting on three feet buzzes against the counter and can shift during the cycle.
- Cabinet touching the counter or an adjacent unit — Why ranked: Fourth. Hand pressure on the cabinet changing the sound is the whole test for this one.
- Wash or drain pump bearing worn — Why ranked: Last, and identified by a noise that tracks the pump exactly and does not change with loading, levelling or cleaning.
What to check, in order
- Turn each spray arm by hand through a full rotation with the racks loaded. — Because: An arm that hits something is hitting it every cycle, and it is free to find and free to fix.
- Pull the filter and check the sump for glass, seeds and bone fragments. — Because: Hard debris in the sump is the classic gritty rattle and it clears without parts.
- Press a hand on the cabinet and the counter edge while it is running. — Because: A sound that changes with pressure is contact and resonance rather than a failing part.
- Note whether the noise is in the wash step or only in the drain step. — Because: A drain-only noise points at the drain pump; noise throughout points at the wash pump or the tub.
Checks you can do safely
- Load as normal, then spin both spray arms by hand and note anything they touch. — N: 1 — Tools: None — Time: quick
- Twist out the filter, rinse it, and feel carefully through the sump with a cloth. — N: 2 — Tools: Cloth, torch — Time: moderate
- Check each foot bears on the floor and adjust until the machine does not rock. — N: 3 — Tools: Wrench — Time: moderate
- Check the cabinet is not pressing against the counter or a neighbouring unit. — N: 4 — Tools: None — Time: quick
- Run a short empty cycle and listen again with the tub clear. — N: 5 — Tools: None — Time: one cycle
Before you open anything
Safety
Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. Broken glass is the most common hard debris found in a sump - use a cloth and good light, never bare fingers. Never reach into the sump with the machine powered. Do not run the machine with the filter removed to see whether the noise stops. Let the tub cool before reaching in after a hot cycle.
When this becomes a service call
A grinding noise remains with a clean sump and free spray arms. The noise appeared alongside poor drainage. There is a burning smell during the drain step. The machine trips its breaker when the pump runs.
Nearest pages
What this page does not cover
This is generalized information for dishwashers carrying the Dencrest Limited name. It does not separate built-in machines from countertop units, whose pumps and mountings differ entirely, and it names no model-specific pump part. Where a family- or model-specific page exists it supersedes this one.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
