In message , geoff
writes

Being a bit hard of thinking ATM, and the only two times I've touched a
washing machine in 20 years was to change bearings or plumb in a new
one, ...

SWMBO is telling me that there are white powdery streaks on some washed
items

What is it ?

Should cleaning out the detergent dispensers and running it empty for a
cycle clear it out, or is there something deeper I haven't thought of ?

what does it smell of?
what texture?
Are the items with the streaks washed at a lower temperature?
Are the dispensers gungy?

It's probably undissolved powder so running it through with some
pre-mixed washing solution & washing soda at max temperature on Cotton
wash should fix it. & yes, clean out the dispensers if necessary.

Is it failing to heat the water sufficiently in the cold weather
perhaps?

--
Si