Kenmore Dishwasher Metallic Smell

My Kenmore Dishwasher after 4.5 years of almost perfect use, has just started to have a "burning or metallic" smell, when in use. A slight cause to worry?
It has run fine and no repairs have been needed, but is this smell something to worry about or does it need some sort of maintenance?

Is the heating element inside the dishwasher covered with a gray or white stuff?

Gene.

where the heating element comes out of the bottom, it is black.
The front left corner has some white to it, but that would be closest to the detergent compartment. The rest of the coil is light white, but the front right corner is more black.
Does the heating coil need to be cleaned? If so, what do you use?

Very possible that smell comes from the heating element. You can clean it as well as a whole dishwasher with white vinegar.

Start the normal cycle (no dishes inside), wait about 2 minutes or until the dishwasher filled up with water, open the door and pour a gallon of vinegar inside. Let it sit there for about 12 hours and then finish the cycle. Repeat this procedure if needed.

Gene.

Thank You!!
I will try it tonight/tomorrow and let you know, how it works and if that is the correct fix for my problem!!