Bosch Dryer Making Noise? Causes & Fix

Quick Answer: Why Your Bosch Dryer Is Making Noise#

Most likely: match the sound to the part. A steady rumble or grind through the whole cycle is the rear drum bearing wearing out; a squeal only at startup that fades within seconds is a glazed drive belt; a high whine or rattle whenever the drum turns is the tensioner-pulley bearing; and a rhythmic thump once per drum revolution is an object caught in the drum or lint area. On heat-pump models a low, steady compressor hum is normal, not a fault. On these compact Bosch dryers, spinning the drum by hand quickly sorts a bad bearing from everything else.

Likely Causes at a Glance#

Walking Through the Diagnosis#

First separate normal from abnormal. Gentle tumbling, a soft airflow whoosh, a click as the door lock engages, and — on the heat-pump WTW models — a low steady compressor hum are all designed sounds. Squealing, grinding, thumping, scraping, or a rising whine are not. Unplug the dryer before you open it.

Let the timing and character point you. A rumble or grind that is present THROUGHOUT the cycle and grows worse over months is the rear drum support bearing, a ball bearing pressed into the back bulkhead; confirm it by opening the door and spinning the drum by hand, where rough or gritty rotation means the bearing and smooth rotation rules it out. Replacing it is an advanced job because the drum has to come out.

A squeal that appears only at STARTUP, when belt load is highest, and then fades within the first thirty seconds or so is a glazed or stretched drive belt (the poly-V belt, BSH 00491680) slipping before it grips — replace the belt before it snaps mid-cycle. A high-pitched whine or rattle that is present whenever the drum turns is usually the spring-loaded tensioner pulley, whose small bearing tends to fail before the larger drum bearing; pull the top panel (a couple of Torx T20 screws) and spin the tensioner by hand, where roughness or play confirms it. A rhythmic THUMP or click, one per drum revolution, is almost always a coin, button, or underwire caught between the drum and a felt seal or lodged in the lint housing — check there and turn the drum slowly to find the contact point. And again, a low unchanging hum on a heat-pump model is just the compressor.

Repair or Replace? The Short Version#

Rule of thumb: if the repair comes in under about half the price of a comparable new dryer and yours is under eight to ten years old, repair it — a belt or a tensioner pulley is inexpensive, and clearing a trapped object costs nothing. A drum bearing is a bigger job but still a targeted repair on an otherwise sound compact Bosch; a noisy sealed heat-pump compressor is the one case that leans toward professional-only service. Our technicians carry Bosch belts, tensioners, and drum bearings — book a repair.

Frequently Asked Questions#

My Bosch dryer squeals at startup then goes quiet — is it serious?#

That is belt glazing: the drive belt slips before it grips, loudest when the load is highest at startup, then quiets once the drum is up to speed. It is not an emergency, but replace the belt soon so it does not break mid-cycle.

There is a grinding sound the whole time it runs — what is it?#

Most likely the rear drum bearing has worn. Open the door and spin the drum by hand; rough, gritty rotation confirms the bearing, while smooth rotation points elsewhere. It is an advanced repair since the drum must be removed.

A thump happens once every drum turn — what causes that?#

Something is caught: a coin, button, or underwire lodged between the drum and a felt seal, or in the lint housing. Turn the drum slowly to locate the contact point and remove the object.

Is the low hum from my heat-pump Bosch dryer normal?#

Yes. Heat-pump models make a steady low compressor hum much like a refrigerator, and that is normal. Only a sudden change — louder, clicking, or new rattling — suggests a developing compressor problem.