The short answer
The short answer for a BlitzHome dishwasher: almost all dishwasher noise is something the spray arm is hitting or something in the sump. Both are found in minutes with the racks out; a pump bearing is where it becomes a replacement decision.
What you actually see
- The machine vibrates against the worktop — A countertop machine that is not sitting flat drums against the surface.
- A grinding sound at the start of the cycle — Grinding at the drain step points at something in the pump.
- The machine buzzes at the drain step only — A buzz with no flow means the pump is energized and blocked.
- A rattle from the base of the machine — Rattles from below the tub are usually the pump or a loose panel.
Causes, ranked for this dishwasher
- Spray arm striking something in the load — The usual answer. a tall item, a handle hanging through a rack or a lid standing proud stops the arm and produces a rhythmic knock. If this is the answer, the rest of the list stops mattering entirely.
- Object in the filter or pump — The runner-up. the sound is confined to the drain step, which distinguishes it from wash-cycle noise. Where this checks out clean, treat the next entry as the working theory rather than a possibility.
- Machine not sitting flat on the worktop — Third. a countertop machine on an uneven surface drums against the worktop, which amplifies a normal pump into a loud one. A clean result here does not just remove one part; it removes everything that depends on it.
What to check, in order
- First — the load and the arm clearance — Reload so nothing overhangs a rack or protrudes into the arm path, then run the cycle again.
- Second — the filter and the sump — Twist the filter out and look in the sump beneath it with a light. Remove anything you find.
Checks an owner can do safely
- Step 1. Level the machine on the worktop — Push each corner down in turn and adjust the feet until all four carry load.
Tools: adjustable spanner or handAbout 10 min
- Step 2. Note when the noise happens — Record whether it occurs during the wash, only at the drain, or throughout. That single fact localises it.
Tools: pen and paperAbout 10 min
- Step 3. Reload with clearance — Reload so nothing overhangs a rack or protrudes into the spray arm path, then run the cycle again.
Tools: noneAbout 10 min
Before you open anything
Safety
Close the supply valve and unplug the appliance before a hose is touched. A capacitor can hold a charge after the power is off. Have towels and a shallow tray ready — a hose that has been under pressure will empty itself the moment it is loosened.
When this becomes a service call
The line is not about confidence, it is about what the next step needs. A grinding at the drain step that persists after the sump has been cleared needs the pump reached from inside the machine.
Sources
General guidance- The Control of Hazardous Energy (Lockout/Tagout) — OSHA 1910.147 and manufacturer service manuals, fetched
Nearest pages
What this page does not cover
What follows is family-agnostic. It names the fault, ranks the causes and gives the order to check them, and it deliberately does not name a board revision, a part number or a model-specific tolerance. Those belong on the family and model pages beneath this one, which are linked under Related pages.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
