Asco Dishwasher: Odor or Mold
A dishwasher that smells is holding food residue somewhere that never dries — most often the filter and the sump, but also the spray arms, the door seal channel and the drain hose. It is a maintenance problem rather than a fault, and it responds to a filter clean and a hot maintenance cycle rather than to any part. Asco sits one letter from Asko; once the machine is genuinely identified it behaves as a conventional appliance and rewards methodical work. All of this is owner work. If the smell survives a proper filter clean and a hot maintenance cycle, the drain arrangement is the next suspect.
What the owner actually observes
- A stale or sour smell when the door is opened between cycles.
- A drain-like smell that is worst when the machine has stood unused.
- A greasy film on the tub walls and the underside of the door.
- Debris visible in the filter or in the sump around it.
- The smell transfers to dishes that have been left in the machine.
- Not this fault: If water is standing in the sump between cycles, fix the drainage first because it is feeding the smell. That is a different fault — see Asco Dishwasher: Will Not Drain (asco-dishwasher-drainage-failure).
- Not this fault: If dishes are also coming out gritty, the same silted filter is causing both. That is a different fault — see Asco Dishwasher: Does Not Clean or Dry (asco-dishwasher-cleaning-performance).
Ranked for an Asco dishwasher
- Food residue in the filter and the sump — Rank: first — Why ranked here: it ranks where it does because the filter catches everything that comes off the dishes and holds it in a warm wet chamber between cycles, and because it is designed for owner cleaning but is very rarely cleaned until something goes wrong
- Short, cool cycles and lightly loaded running — Rank: second — Why ranked here: eco and quick cycles never reach a temperature that clears grease, so a machine used only on short programmes accumulates residue that hotter cycles would have removed
- A different machine than the one being read about — Rank: third — Why ranked here: ranked here only because this badge is a single letter from another one; it costs nothing to rule out and it invalidates everything downstream if you do not
- Grease and residue on the tub, the door seal channel and the door edge — Rank: fourth — Why ranked here: the strip of tub above the water line and the channel the seal sits in never get washed by the spray, so grease accumulates there and is the source of the smell that is strongest at the door
- Blocked spray arm jets holding debris — Rank: fifth — Why ranked here: the arms are hollow and hold water and debris inside them between cycles, which makes them a reservoir as well as a delivery system
- The drain hose or the waste connection — Rank: sixth — Why ranked here: a drain-like smell that is worst after the machine has stood unused usually comes from the waste rather than the appliance, particularly where there is no high loop in the hose
- Note: Because the badge is one letter from another and confusing them changes the answer, the order below confirms the machine first, then works the conventional dishwasher chain — water in, wash, heat, drain — in that order, because each stage depends on the one before it.
Check in this order
- The filter assembly and the sump beneath it, unscrewed and lifted out — Order: first — Because: it is free, it is the largest single reservoir, and it explains a smell and poor washing together
- The door edge, the seal channel and the tub above the water line with a cloth — Order: second — Because: it is free, it takes minutes, and it is the area the machine cannot clean itself
Owner-safe checks
- Confirm the badge on the data plate matches the badge you searched for. If the plate reads Asko, use the Asko page instead — the platforms differ and so do the parts. Once the plate confirms the machine, work the water path from the fill valve forward. — Step: first — Tools: a torch and a phone camera — Time estimate: a few minutes
- Unscrew and lift out the filter assembly, rinse every part under a tap with a brush until the mesh is clear, and clean the sump beneath it, wearing gloves because of glass. — Step: second — Tools: a brush, gloves, warm water — Time estimate: under a quarter of an hour
- Wipe the door edge, the seal channel and the strip of tub above the water line with a cloth and a little detergent. That area is never reached by the spray and it holds the grease that produces the smell at the door. — Step: third — Tools: a cloth, detergent — Time estimate: under a quarter of an hour
- Remove the spray arms, rinse them through and clear any blocked jets, then refit them and check they turn freely. — Step: fourth — Tools: a cocktail stick or fine wire — Time estimate: under a quarter of an hour
- Run the hottest cycle the machine offers, empty, with a dishwasher cleaner, then leave the door slightly ajar between cycles from now on so the tub dries. — Step: fifth — Tools: a dishwasher cleaner — Time estimate: one long cycle
- Read the data plate on the door edge or the tub rim and check the spelling of the badge against the one you searched. Then run the chain in order — fill, wash, heat, drain — and stop at the first stage that misbehaves rather than at the first part you suspect. — Step: sixth — Tools: a phone camera, a torch — Time estimate: a few minutes
- Stop condition: Stop before removing the sump housing or the drain hose; those need the machine pulled out from under the worktop.
Safety
Safety
Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. Dishwasher filters and sumps routinely contain broken glass, and cleaning products must never be mixed inside the tub. Wear gloves when clearing the filter and the sump, since fragments of glass collect there. Never mix bleach with any acidic descaler or cleaner inside the machine, and run a rinse between different products. Wear gloves when clearing the filter and the sump, since fragments of glass collect there. Never mix bleach with any acidic descaler or cleaner inside the machine, and run a rinse between different products. unplug-before-service
When to call a technician
The line is when the accessible surfaces are clean and the smell persists. Call if the smell returns quickly after a thorough filter clean and a hot maintenance cycle. Call if water stands in the sump between cycles, since a drainage fault is feeding the smell. Call if the smell is of drains rather than of food, which can indicate the waste arrangement rather than the machine. Call if there is standing water beneath the machine as well as a smell.
Nearest pages of the same kind
What this page does not cover
This page is generalized across every family and model sold under the Asco badge. It does not carry model-specific error-code tables, family-specific service procedures, sealed-system work or parts numbers, and no model-specific page exists beneath it yet — the data plate on your unit is the authority, not this page. For the other faults on this appliance, start from Common Asco Dishwasher Problems (asco-dishwasher-problems) and pick the symptom that matches.
Links: - [Common Asco Dishwasher Problems](/blog/asco-dishwasher-problems) - [Asco Dishwasher: Abnormal Noise or Vibration](/blog/asco-dishwasher-abnormal-noise) - [Asco Dishwasher: Does Not Clean or Dry](/blog/asco-dishwasher-cleaning-performance) - [Asco Dishwasher: Controls, Display or Error Code](/blog/asco-dishwasher-control-fault) - [Asco Dishwasher: Cycle Will Not Run or Complete](/blog/asco-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.
