I have a new 2006 Elantra GLS with only 675 miles, which has developed its first (seemingly) abnormal noise. I say "seemingly," because perhaps it's normal. I plan on taking it in to the dealer for a listen, but also thought I would post it here in case anyone (Hyundaitech?) may have any ideas.
The noise appears to occur when the engine is at operational temp, and is most noticeable from around 1900 to 2100 RPM. The noise is present at in Park or Neutral, or when driving at those RPM ranges.
I wish I would include a audio file, but it sounds kind of like a low to mid-pitched "rrrrrrr" with a lower-pitched rumble (almost like a bad bearing). It's coming from the crankshaft and accessory belt drive side of the engine (left-side when facing the car). I spent some time with a mechanic's stethoscope this evening, and couldn't come up with anything localized or definite. I do know it's coming from the bottom-half area of the timing belt cover area, but it's really hard to pinpoint the source.
I know it could be anything, but is it normal for the timing belt tensioner to make some noise? If not, and if it's the timing belt tensioner, do they prematurely (infant mortality) fail occasionally? Another possible source may be the AC belt tensioner, below the AC compressor. Or, possibly even the alternator bearing. I know I'm grabbing at straws here, but it certainly doesn't sound normal, and neither my wife or I have heard it until today, as the car makes more noise even at idle than before.
The only thing that I've ever heard even close to the "rrrrrrr" sound is what some of the GM X-series (Celebrity, 6000, Cutlass Ciera, etc.) cars used to sound like from inside the cabin, and I think that sound was transaxle related.
Obviously, it's off to the dealer for some troubleshooting. I just hope the tech can hear it . . .