Kinda lengthy description - 07 santa fe 3.3 127K mis. Was changing what I think was original belt. Noticed what looked like oily goo on alternator near pulley (oil change place said I had a front valve cover leak). Was not oily goo appeared to be clumps of rubber melted together. Scraped larger stuff off. Noticed black rubber dust in some areas, looked like oily goo. Put on new belt, after 1800 miles the smooth side of the belt if you rub your finger on it rubber dusty stuff comes off on finger. Premium belt, no spotting or obvious leaks where fluid could be getting on belt and degrading it. Idler and tensioner smooth and not wobbly, no weird noises. Any ideas on belt wear or fluid getting on belt? Pics posted. P1 alternator, P2 tensioner pulley, P3 PS pump and pulley, P4 place on front where I finger wiped black dusty stuff.
Old belt smooth side was smooth and shiny, new belt grooved portion looks fine. I think the oil change place thought the black crap was from an oil leak.

 

Other than a very tight drive pully EG Alternator seizing up, which may cause slipping of the driving size of the belt. Have you cleaned the rocker gasket area and above the alternator. I'd vacuum what you can trying not to get it into the alternator as it may cause it to fail. Oil is pretty much the only other reason if all the inline components are working fine. Alternators being killed and shutting down the vehicle (3.3L especially) is well documented problem with the gasket leaking. I am not sure if compressed air to clean or blow out what might be in the alternator would help or not that would be your call.


Good luck with it.

 

Look for a power steering pump leak and check for valve cover gasket leak. I would say some type of oil is getting on the belt.