elantra oil color

Are you referring to a waxy buildup underneath the oil filler cap?  If so, I would not be concerned so long as the crankcase oil on the dipstick looks good.  I've always associated this buildup with engines running under more humid conditions, particularly during the winter when crankcase condensation is more likely occur when the engine cools down.  I think the buildup is worse when an oil formulated with a higher paraffin content is used.  Conventional Quacker State and Pennzoil use to be notorious for this.   I also think the buildup is worse on engines that are started and shut down before they have a chance to run for a period of time at operating temperatures.  Over time, moisture levels build up inside the engine since the engine is never hot enough, long enough to completely volatilize the moisture in the crankcase.  Short commutes and test drives come to mind.