Bosch Dryer Makes Noise: How to Troubleshoot

Unplug before you inspect anything and never reach into a running drum. Give the machine ten minutes to cool first — heat pump condensers stay hot after a cycle.

Match the sound to the part#

Two minutes of free diagnosis#

Run the dryer empty. If the noise vanishes, it was a zipper pull, a button or a coin knocking around the drum, and you are done.

If it persists, open the door mid-cycle and turn the drum slowly by hand. Where you feel the noise tells you the zone: grinding you can feel through the drum surface is a bearing or seal, while a sound from below and forward is the idler pulley or the blower fan.

Belt and idler#

Take off the top panel and the right side panel. A belt that has gone glazed and shiny is what squeals; cracking or fraying means it is close to breaking outright.

Then push the idler pulley round with a finger. It should spin freely and silently. Any grinding or roughness through your fingertip means the bearing has gone and the pulley gets replaced.

The felt drum seals#

Front and rear felt strips seal the drum edges so air cannot escape around them. Once a strip wears through, bare metal drum runs against the housing, which is exactly the scraping and grinding sound people describe. Look at the drum edges through the open door for shiny wear marks — they are easy to spot once you know to look. Worn seals get replaced, not patched.

Blower fan and support rollers#

The blower fan is reachable from the rear panel on most models and collects lint and debris over time. A foreign object striking the blades gives you rapid clicking; a cracked or broken blade gives an unbalanced whirring instead. Pull the rear panel and look at it directly.

If your model has drum support rollers — small wheels the drum rests on — worn bearings there produce a rumbling or thumping that is loudest with an empty drum, because clothes damp the vibration. Replace them as a set rather than singly, so the drum sits evenly.

What can wait, and what cannot#

Not every noise has the same urgency. A squealing belt or idler will usually run a few more weeks, though a seized idler can overheat and chew through the belt quickly — a week is a sensible limit. Grinding or scraping is different: drum-to-housing contact causes damage and heat build-up, so stop using it. And rattling from the blower area deserves immediate inspection, because lint accumulated near a heat source on vented models is a fire risk.

Torx T20 is the fastener for every panel, and 400-grit sandpaper covers sensor cleaning; nothing here needs specialist tools. Well maintained, these machines run 12 to 15 years, and heat pump models often longer because they have fewer wear parts. Under 8 years a repair is nearly always worth it; between 8 and 12 it depends on the part, though belts, sensors and handles are always worth fixing.

Sealed heat pump work, compressor faults, or anything involving 240V you are not comfortable around is where to stop. Book a repair and we will identify it properly.