We have a bleach dispenser in our new LG washing machine .. however it just has a hole in the bottom and goes straight into the wash drum ... is ther something missing ?

SOURCE: detergent dispenser

As far as I am aware, there IS NO dispenser for bleach, you have to put bleach in drum before adding clothes and starting cycle. The far right compartment is only for "pre-wash" cycles, and if no pre-wash is selected, water will run through ALL compartments at the rinse stage..... Oshie

SOURCE: Bleach and fabric softener dispensers full of water

This is a problem common to virtually all front-loaders. Pull the dispenser drawer right out (it is designed to come right out - you might just need to give it a bit of a jiggle to get it past the stop) Remove the cover/caps from the drawer (sometimes this is a snap-on cover over the back of the drawer, sometimes a top-hat shaped cover over the siphon spigots). Give everything a thorough clean off with hot water (scrubbing with an old toothbrush helps), then reassemble. A.

SOURCE: LG WM2233H Washer

Most likely the small electric motor that moves the water injection pipe on to the various outlet mainifolds has stripped its plastic gears, afraid the only solution is a new soap dispsener assembly

SOURCE: Front Load Washing Machine

Filling laundry detergent and/or additive 
dispensers 
Dispenser I: (RIGHT SIDE)
Detergent for soaking agent. 
Dispenser II: (LEFT SIDE)
Detergent for wash, stain remover. 
Dispenser 2: (MIDDLE)
Cleaning product, e.g. fabric softener, fabric 
conditioner (do not fill above the lower edge of the 
insert 1). 

SOURCE: Fabric Softener & bleach dispensing

The control board program has many sensors built into the unit to determine when to dispense the bleach and the softener.  LG tech documents doesn't list when these liquids are dispensed so there must be a program that matches the current operation and loads of each wash program.  That's the best answer I can give you at this time.