Toyota: Windshield wipers, toyota rav4, windshield wipers

Question
I own a 2000 Toyota RAV4 with 19,000 miles.  Recently I changed the front windshield wipers.  The wipers cost $4.99 each and Autozone installed them for me on the spot.  Everything was fine for two weeks and then the wipers started making noises whenever they were used.  It is not a scratchy noise but more like a motor noise.  Can I put some WD 4 oil onto it?  Do you know the cause of the noise?  Maybe the wipers are not compatible?

Answer
As far as compatibility of wipers goes, it's based on how good (or bad) their quality is and if you bought both at the right length.  Is there a better way you can describe the noise?  19,000 mi on the odometer?  I don't want to say it's the wiper motor because it's too young.    

How about this: Try spraying water on your windshield and then run the wipers, if you can hear the noise while it's wiping the water off, it could possibly be the wiper motor.  My wipers make noise like crazy (when they get all the water off my windshield) but it's because they've got little cracks in 'em since the rubber is OLD.  But, I'm toooo lazy to change 'em:)  Try this out and get back to me:)

One other thing: If the length is incorrect, it could be wiping outside of the windsheild area.  Check both wipers to see they don't get off the windsheild.  I do remember trying the wrong length blades on my car and it gave a pluck type of sound.