I'm trying to diagnose a problem I'm experiencing, which is a peculiar sound coming from the engine compartment. The sound is a whine, almost like a turbo sound, when the engine revs above 1,500 RPM (no matter if car is moving or standing still). It started very faintly about 4 months ago and is slowly getting louder over time.
I can definitely rule out the alternator, drive belt, and idle pulley, as the sound persisted with the drive belt disconnected.
If it is not the water pump, I'm thinking that perhaps it is something to do with the timing chain. The engine has 132,000 miles on it, very well cared for and not abused.
I highly doubt it is the chain itself, as these seldom wear out at this mileage. I'm guessing that it might be a chain tensioner or guide. When these parts begin to wear, what kind of sound could they make? Could it be the sound I described above? Or would these parts when worn only cause a rattling noise?
I do not trust the Nissan dealer service center that took my car for
*3* days to diagnose it and is now thinking it "might" be the water pump ($400 in labor) or else an internal engine exploration is needed ($1500 in labor). This is criminal. I'm hoping someone can say "ah yes, I know what that sound is--" and save me some $$.Thanks for any advice!