We have an LG dishwasher that sat in storage brand new unboxed for 10 years, until we moved and installed it in the new house. Well, it's making an awful grinding noise only during the first 20 minutes of pre-wash, after which it goes away and washes the dishes perfectly. When I open the door in pre-wash there's barely any water dripping down. What's it doing so different in pre-wash? My guess is the food disposer is running. Is this dishwasher past its lifespan or saveable?

Edit: Model is LDF6920ST

Link to sound

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    I'm unable to hear anything other than seemingly normal dishwasher noises. Can you add the model number of your dishwasher to your question by clicking the edit button and modifying the text accordingly please? I think that will help people answer this question better. Commented Nov 25, 2020 at 13:53
  • Added the model. Please listen again. The grinding that's not in line with the rest of the audio is definitely not normal. Check 0:10.
    – Steven
    Commented Nov 25, 2020 at 22:46

1 Answer 1


We have an LG dishwasher as well and it does the same after a few years of operation. Currently its still grinding away but washes well, like you mentioned. I did some research before and it seems that for us its either the:

  1. Circulation Pump
  2. Circulation and Drain Pump Motor

It seems like our source of problem is when water is being circulated and not any drains since towards the end, when the drain is working, little noise is produced.

I have promised myself that I will do some troubleshooting to Identify root cause but haven't done yet.

Source: https://www.repairclinic.com/RepairHelp/How-To-Fix-A-Dishwasher/35-200--/Lg-Dishwasher-Making-Noise

  • Water doesn't drain during the main wash either, so it's still confusing why it's ONLY during the first 20 mins of pre-wash. It's barely been in use for a year. I do wonder if sitting in storage for 10 yrs caused some rusting or deterioration of the internals.
    – Steven
    Commented Nov 25, 2020 at 22:43
  • Might guide you further: If the machine works fine other than the grinding sound, there is a blade that is in the center and grinds up residue, somtimes it gets a object in the space and wont grind it up.If you are ok at taking things apart and puting back together,disasemble the center sprayer, screen and tube to top sprayer, the blade is under the screen housing.clean out and reasemble and should work fine. not hard to do really, when you reasemble do not tighten screws as you intall them as they allign everything,intall then all loose then tighten snug NOT to tight as they go into plastic.
    – Paul M
    Commented Nov 25, 2020 at 23:33
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    appliancejunk.com/forums/index.php?topic=20453.0. theres a good video of taking apart unit and seeing the grinder blade.
    – Paul M
    Commented Nov 25, 2020 at 23:36
  • Thanks for the guide. So I followed it, taking the filter apart to the grinding blade, but saw no food or anything awry. When I put it back together, I ran the dishwasher empty a couple times and it seemed to be miraculously fixed. But get this -- when I ran it again full of dishes, the problem was back. Obviously it must be a coincidence, but I'm starting to lean towards just replacing the damn thing.
    – Steven
    Commented Nov 26, 2020 at 10:49

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