The short answer
On the WQG line, the most common reason a dryer is making an unusual noise is blower wheel loose, cracked or fouled. On this page that cause is ranked ahead of a foreign object in the drum or the blower, which is where the order departs from the brand-generic article above; the ranking below says what about this platform moved it. Two of the four causes below are owner-checkable with no tools worth naming, and the last of them is a service call.
What you see on the WQG line
- A high squeal that rises with the drum — A dry idler or a glazed belt makes this, and it usually gets worse as the machine warms.
- Grinding or scraping from the back of the cabinet — Rollers and bearings live there, and both announce themselves by grinding rather than squealing.
- A rattle that changes with the load — Coins, buttons or a pen in the drum seam, or an object caught between the drum and the bulkhead.
- The whole machine walking or shaking — Feet out of adjustment, or a floor that flexes, turns ordinary vibration into movement.
- NEAR MISS — noisy and the load stays wet — A blower wheel that has come loose makes noise and kills airflow; read the heating page too.
Causes, most likely first on the WQG line
- Blower wheel loose, cracked or fouled — A blower wheel is a plastic hub on a steel shaft, and when that hub cracks or its nut loosens the wheel wobbles. The noise runs continuously, the airflow drops, and the drying time goes up alongside it. It is the one noise on the list that is also costing you drying performance, which makes it worth finding early rather than late. Five models sit under this family key. They are close enough relatives that a fault found on one is worth suspecting on the others.
- A foreign object in the drum or the blower — Coins, buttons, hairpins and pen caps escape pockets, pass the drum seam and end up either trapped at the front seal or fired into the blower wheel. The noise is loud, alarming and usually free to fix. The only one that can be cleared in five minutes with nothing but a torch.
- Drum support rollers worn flat — Support rollers wear on one side first, and the flat they develop lands once per drum revolution. The noise is regular, it is load-independent, and it gets louder as the machine warms up. It ranks here because the rhythm of the noise identifies it with more confidence than most appliance symptoms allow.
- Rear drum bearing or glide worn through — The rear of the drum runs in a bearing or on a felt glide, and when that wears through the drum runs metal on metal. The sound is a grind rather than a thump, and it deepens week by week. It stays last because it is the least common of the group and the only one where continuing to run the machine damages the drum itself.
Check in this order, and why
- First: Does the noise continue with the drum empty and the vent clear? — Noise unchanged by the load points away from the drum and toward the blower. It comes first because it is the cheapest of the four to exclude and because everything below it is harder to read while it is unresolved.
- Second: Turn the drum slowly by hand with the power off, listening — Check the drum seam and the lint filter housing, and shine a torch into the blower housing if you can reach it.
- Third: Spin the drum by hand and feel for a repeating bump — A thump at the same point each turn is the roller path, not the belt.
- Last: Is the noise a grind rather than a thump or a squeal? — Grinding that worsens week by week is a bearing, and it is a technician job.
Before you open anything
Safety
Switch off at the breaker before any panel comes off and treat the capacitor as charged afterwards. Turning the drum by hand is safe with the power off and is the only way this diagnosis should be done. If you smell gas at any point on a gas machine, leave the building and call the gas utility or 911 from outside.
Models in the WQG family
Reference| Model number | Family key |
|---|---|
| WQG235D8AU | bosch:dryer:wqg |
| WQG235DRAU | bosch:dryer:wqg |
| WQG24200AU | bosch:dryer:wqg |
| WQG24201AU | bosch:dryer:wqg |
| WQG24203AU | bosch:dryer:wqg |
When to call a technician
The line is the cabinet: anything reachable through the door or the lint housing with the power off is yours, and anything behind the front or rear panel is not. A rattle can wait for an appointment; a grind should not.
