Solved

Black streaks and marks on white washing

LOLongman S
Asked almost 5 years ago 4,283 views
0

I keep getting black streaks and marks on white washing from my Bosch washing machine / tumble dryer. I have has a service engineer come out and he could not find the reason replaced the door seal. First was after this and it happened again on a pair of cream denim trousers. The machine is 1 year old. and this started about 6 months ago. Has anyone else had this happen

Solution Summary

AI-generated from this discussion

This thread was marked as solved. Here's a summary of the problem and the fix, generated from the discussion below.

Washer-dryer leaving black streaks on light-coloured washing

The problem
A Bosch washer-dryer, under one year old and used about twice a week, was leaving intermittent black streaks/marks on white or cream items. A service engineer had already inspected it and replaced the door seal, but the marking recurred afterwards.
Likely cause
The strongest diagnosis in the discussion was laundry being trapped and dragged around the door seal area, particularly near the dryer air vent at the top of the seal, causing long black marks. Build-up from repeated 30°C washes with liquid detergent was suggested initially, but this was weakened because the machine was reported clean, the drum had been checked, and Bosch cleaner was used regularly.
What fixed it
Recommended action was to inspect and rub a light-coloured cloth firmly around the door seal where it meets the drum lip and around the top vent area to try to reproduce the marks and identify contamination or snagging points. Overloading was mentioned as a common explanation on washer-dryers, but no confirmed repair was posted.
Checks to try
  • Service engineer inspection
  • Door seal replaced
  • Door seal reported clean with no gunge
  • Drum checked and reported clear of gunk
  • Bosch cleaner used every 2 months
  • Inspection/rubbing around the door seal and top dryer vent was suggested
Parts or tools mentioned
  • Door seal
  • Light-coloured sheet or cloth
  • Bosch cleaner
Cause identifiedGenerated 15 Aug 2026 · AI summaries can make mistakes — read the full thread below.
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8 Answers

Accepted Answer
0
WH
WhitegoodshelpVerified Engineer
Answered almost 5 years ago

Hello Susan. Do you mean it is a washer-dryer or that you aren't sure if it is the washing machine or the tumble dryer? I'm presuming it is a washer dryer?

Can you tell me what wash cycle you use most and its temperature? And do you use liquid detergent?

Whitegoods Help — appliance repair expert and forum host.
0
LO
Longman S
Answered almost 5 years ago

Hi Andy it is a washer/dryer. This has happened on various washes usual temp is either 30degree Cotton and 60degree cotton Gentle dry. Yes I used to use non bio liquid. Thanks

0
WH
WhitegoodshelpVerified Engineer
Answered almost 5 years ago

Hi. Using mostly 30 degree washes and liquid detergent can cause a big build up of grease, grime and even black mould inside washing machine.

Was the door seal that got replaced covered in gunge? Also have a look under the door seal under the lip of the revolving drum to see if there is any nasty stuff.

Whitegoods Help — appliance repair expert and forum host.
0
LO
Longman S
Answered almost 5 years ago

No the engineer said it was very clean and clear of fluff or anything. Drum checked and no gunk also I use Bosch cleaner every 2 months. The marking doesn’t happen on every wash, also I now use laundry strips.

0
WH
WhitegoodshelpVerified Engineer
Answered almost 5 years ago

Tbh it does normally take a few years to get bad. If washing machine is nice and clean it’s hard to imagine where black marks could come from.

Washer-dryers have a vent at the top of the door seal where the hot air for drying is blown into the drum. It’s very common for laundry to get caught on it especially if overloaded. Try rubbing a light cloth around up there to see if you can find anything.

Other than that I can only point you to my article washing not getting clean or has marks on it in case it has anything useful.

Whitegoods Help — appliance repair expert and forum host.
0
WH
WhitegoodshelpVerified Engineer
Answered almost 5 years ago

If you could post any photos it might help too.

Whitegoods Help — appliance repair expert and forum host.
0
LO
Longman S
Answered almost 5 years ago

Hi Andy Have tried that. The machine is not a year old yet and only gets used Twice a week

0
WH
WhitegoodshelpVerified Engineer
Answered almost 5 years ago

Try getting an old light coloured sheet or cloth and see if you can replicate the marks by dragging it firmly around the door seal where it meets the lip of the drum and up at the top where the vent for the dryer is.

Essentially, as the laundry is inside a steel drum and the marks are long it can only really be caused by laundry getting trapped and dragged around the door seal.

It seems to be common in washer-dryers though manufacturers usually blame overloading.

Whitegoods Help — appliance repair expert and forum host.

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