The short answer
On a DCS dishwasher, what the noise is and whether it matters comes down to a short list, and on this line the order is not the generic one. The diagnosis starts at the seal on whichever layout you actually have — drawer lid or hinged door, because the older badge covers both layouts, so the first job is establishing which one is in front of you: the seal that fails is a different part, in a different place, in each case. The first three checks below need no tools and no parts; the point at which this stops being an owner job is stated further down, as a condition rather than as a recommendation.
What you are seeing
- A grinding or rattling that comes and goes through the wash.
- A rhythmic knock as the spray arm turns and strikes something.
- A high-pitched whine during the drain.
- A humming with no water movement at the drain phase.
- A thump when the machine changes phase, which is often normal valve action.
- A buzz that varies with how full the tub is.
- Note: Near-miss symptoms that mean a different fault: If the noise comes with water on the floor, treat the leak first. If the noise comes with standing water, treat it as a drainage fault. Valve clicks and a soft thump at phase changes are normal on nearly every machine.
Causes, ranked for a DCS dishwasher
- The seal on whichever layout you actually have — drawer lid or hinged door — Why this rank: The older badge covers both layouts, so the first job is establishing which one is in front of you: the seal that fails is a different part, in a different place, in each case.
- Loose racks, a missing rack stop or a broken tine — Why this rank: It rattles with the water rather than with the machine, and it is diagnosed by running a cycle empty.
- A machine not level or not secured to the cabinet — Why this rank: An unsecured machine walks and drums against the counter, and the noise rises with the load.
- Water hammer at the fill valve — Why this rank: It is the household plumbing rather than the machine, and it is identified because it happens only at fill.
- The drain hose slapping against a cabinet — Why this rank: It sounds like it comes from inside the machine and it is fixed with a cable tie.
- The spray arm striking an item in the rack — Why this rank: It is the most common noise complaint on any dishwasher and it is corrected by moving one dish.
What to check, in order
- Run a cycle with the machine completely empty and listen. — Order: First — Why: It removes the load and the racks from the list in one cycle, and the two of them account for most complaints.
- Note which phase the noise happens in — fill, wash or drain. — Order: Second — Why: The three phases use three different pumps and valves, so the phase names the part.
- Remove the filter and sump screen and search the sump by hand for glass, seeds or bone. — Order: Third — Why: It is the second cause, it needs no tools, and hard debris in a pump gets worse the longer it runs.
- Check that the machine is level, its mounting brackets are tight, and the drain hose is secured. — Order: Fourth — Why: It removes the whole class of contact and drumming noise cheaply.
Steps a homeowner can take
- Switch the machine off at its breaker before reaching into the sump or removing the toe kick. — Tools: none — Time: a moment
- Run a short cycle completely empty and note whether the noise is still there. — Tools: a watch — Time: an hour or more
- Remove the filter and sump screen, and search the sump with a gloved hand and a flashlight. — Tools: gloves, flashlight — Time: half an hour or so
- Spin each spray arm by hand with the racks loaded as usual, and move any item it touches. — Tools: none — Time: several minutes
- Check the rack stops and tines, and refit any rack that is not sitting on its rollers. — Tools: none — Time: several minutes
- Check the machine is level and its mounting brackets are secure, and cable-tie any loose drain hose. — Tools: spirit level, screwdriver, cable tie — Time: half an hour or so
Before you start
Safety
Switch the machine off at its breaker before reaching into the sump or removing the toe kick. A capacitor can hold a charge after the power is off. The sump routinely contains broken glass — use a glove and a light, never bare fingers. Do not run a machine with a known hard object in the pump; it will destroy the impeller.
When this stops being an owner job
Call when the noise persists with the machine empty, the sump clear and the arms turning freely, or when it is a grinding from the pump housing. A pump that is worn rather than obstructed is replaced from underneath with the machine drawn out.
Sources
General guidance- The control of hazardous energy (lockout/tagout), and manufacturer service-manual practice — OSHA 1910.147 / manufacturer service manuals, fetched 2026-09-06
Nearest pages
Generalized information
This page is generalized: it covers DCS across a whole dishwasher range rather than one family or one model, and where a more specific page exists it is linked here. It does not cover the current DCS by Fisher & Paykel badge and model-level pages, and it does not carry serial-range or model-group detail — check the rating plate before ordering any part. DCS by Fisher & Paykel Dishwasher: Abnormal Noise or Vibration — Slug: dcs-by-fisher-paykel-dishwasher-abnormal-noise — Covers: the DCS by Fisher & Paykel line specifically
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
