The short answer
Noise from a Costway compact dishwasher is usually the machine vibrating against the worktop or an item fouling the spray arm rather than a failing pump. A light machine on a hard worktop transmits every vibration into the surface, and the single spray arm is easily blocked by a tall item.
What you are actually seeing
- A rattle that changes when you press on the machine — Means: on-page
- A knocking that matches the spray arm turning — Means: on-page
- A buzz that is far louder on a hard worktop than on a mat — Means: on-page
- A grinding from the base of the machine — Means: on-page
- A rattle from items in the rack — Means: on-page
- A gurgling during the drain step only — Means: different-fault — Go to: costway-dishwasher-drainage-failure
- A buzz with no cycle running — Means: different-fault — Go to: costway-dishwasher-electrical-safety
- Body: Match what you see before you take anything apart. A rattle that changes when you press on the machine. A knocking that matches the spray arm turning. A buzz that is far louder on a hard worktop than on a mat. A grinding from the base of the machine. A rattle from items in the rack. Some near-miss symptoms belong on a different page: A gurgling during the drain step only points at the drain hose position, covered on costway-dishwasher-drainage-failure; A buzz with no cycle running points at an electrical fault, covered on costway-dishwasher-electrical-safety.
Causes, ranked for this machine
- The machine vibrating against a hard worktop — Why this rank: First because it is a light machine on a large flat resonant surface, and a mat under it usually removes the complaint entirely
- An item in the rack fouling the spray arm as it turns — Why this rank: Produces the most alarming noise from the most trivial cause
- The machine touching a wall, a splashback or another appliance — Why this rank: Contact transmits vibration into the kitchen structure
- A hard object that has reached the base, such as a stone or a piece of glass — Why this rank: A grinding from the base is this until proven otherwise, and leaving it damages the pump
- A worn pump or spray arm bearing — Why this rank: Last because it needs a part and the four above account for most calls
- Body: Ranked for a countertop or portable dishwasher that connects to the kitchen tap with a quick-connect adapter or fills from an internal tank, and drains through a hose into the sink. Most likely: The machine vibrating against a hard worktop. First because it is a light machine on a large flat resonant surface, and a mat under it usually removes the complaint entirely. Next most likely: An item in the rack fouling the spray arm as it turns. Produces the most alarming noise from the most trivial cause. Third: The machine touching a wall, a splashback or another appliance. Contact transmits vibration into the kitchen structure. Fourth: A hard object that has reached the base, such as a stone or a piece of glass. A grinding from the base is this until proven otherwise, and leaving it damages the pump. Fifth: A worn pump or spray arm bearing. Last because it needs a part and the four above account for most calls.
What to check, in order
- Press on the machine while it runs and listen for the noise to change
- Spin the spray arm by hand with the rack loaded to check for contact
- Move the machine clear of the wall and stand it on a mat
- Check the base under the filter for a hard object
- Body: Each check rules out the causes above it. First, press on the machine while it runs and listen for the noise to change. Second, spin the spray arm by hand with the rack loaded to check for contact. Third, move the machine clear of the wall and stand it on a mat. Fourth, check the base under the filter for a hard object.
Checks you can safely make yourself
- Press down on the top of the machine while it runs and note whether the noise changes or stops — Tools: none — Time estimate: a few minutes
- Spin the spray arm by hand with the rack loaded and check it turns a full circle without touching anything — Tools: none — Time estimate: a few minutes
- Stand the machine on a rubber mat and move it clear of the wall and any splashback, then run a short cycle — Tools: mat — Time estimate: a quarter of an hour
- Unplug the machine, lift out the filter and look into the base with a torch for glass, stones or bone — Tools: torch, gloves — Time estimate: a quarter of an hour
- Run a short cycle with the machine empty and note whether the noise persists — Tools: none — Time estimate: one short cycle
- Body: Checks an owner can make with the machine unplugged or by watching a short cycle. Step one: Press down on the top of the machine while it runs and note whether the noise changes or stops. Tools: none. Time: a few minutes. Step two: Spin the spray arm by hand with the rack loaded and check it turns a full circle without touching anything. Tools: none. Time: a few minutes. Step three: Stand the machine on a rubber mat and move it clear of the wall and any splashback, then run a short cycle. Tools: mat. Time: a quarter of an hour. Step four: Unplug the machine, lift out the filter and look into the base with a torch for glass, stones or bone. Tools: torch, gloves. Time: a quarter of an hour. Step five: Run a short cycle with the machine empty and note whether the noise persists. Tools: none. Time: one short cycle.
Safety first
Safety
Unplug the machine before reaching into the base, and wear gloves: a hard object in the base is often broken glass. Do not run the machine with a known object in the base, because it will reach the pump. Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. unplug-before-service
Where the owner fix ends
Call a technician, or claim under warranty, when an empty cycle on a mat, clear of every surface, still produces the same grinding or knocking with the base clear. That is the pump or an arm bearing, which is inside the machine.
Nearest pages of the same kind
Generalized information
This page is generalized across the Costway dishwasher line. Countertop machines with an internal tank, countertop machines on a tap adapter and rolling portable machines share the ranking above but not every part, and this page does not cover a specific model or control revision. Family- and model-specific pages, where they exist, are linked below.
Links: - [Common COSTWAY Dishwasher Problems](/blog/costway-dishwasher-problems) - [COSTWAY Dishwasher: Does Not Clean or Dry](/blog/costway-dishwasher-cleaning-performance) - [COSTWAY Dishwasher: Controls, Display or Error Code](/blog/costway-dishwasher-control-fault) - [COSTWAY Dishwasher: Cycle Will Not Run or Complete](/blog/costway-dishwasher-cycle-fault)
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
