Front Hood Detective -- alternator, tensioner pulley or water pump?
Just updating my previous thread that got me stumped and continues to get me stumped. It's about this intermittent whir sound that occurs from time to time. Unlike the last time where I thought it was a transmission related problem (as it occurred in live downtown traffic), this time I managed to pop up the hood in a quiet area and managed to still hear the sound after I reached my destination. I couldn't replicate it again when I got home, unfortunately... Vehicle involved: 2010 Acura RDX, 86000kms...
The sound emanates from somewhere where there's a serpentine belt spinning around the pulleys/alternator. At this point it could be either one of the few things but just venturing out a post to see what you guys think. It's an intermittent whir and doesnt occur all the time - the last time it happened was 2-3 weeks ago (which was also the first time it happened). Have driven ~1000kms since the last time it occured. My own research in youtube, internet, owners manual yields me some hypothesis:
a) Alternator -- all my research indicates that if it's the alternator giving out soon, the whirring sound is constant, not intermittent (?). HOWEVER, THE SOUND I HEAR FROM OTHER VEHICLES THAT HAVE SUCH ISSUE IS SIMILAR TO MINE (or at least close to it)... ALT nor Battery light isnt lit and certainly, power draw while using heater, radio, headlights doesnt change... Based on what I read if this is the part giving out, then these symptoms should be apparent? Maybe I should wait longer to see if the whirring sound becomes constant? (hence this is my #1 suspect, FWIW)
b) Tensioner pulleys -- the whirring sound does not sound like grinding nor bearings being crushed. But it still could be since it's within the area near the belt
c) Power Steering Pump -- It doesn't happen when I turn though, it also happens while I'm moving on stop go traffic at low speeds (at least that's when it happened the last time)
d) Water Pump -- no clue but maybe?
e) Serpentine Belt -- it is not a squealing high pitched sound but more a whir
Should you wait for whirring to occur constantly so that it's easier to diagnose when brought to the shop? or proactive replacement of all these above including serpentine belt since it'll probably dismantle everything? needless to say, it's a debate whether one does proactive replacement (but incorrect parts replaced and therefore problem unsolved since intermittent sound) or wait for constant whir sound (but then it might be too late and get stalled on the road)
FWIW- i called dealership to ask and obviously, the usual "we dont know we have to run computer tests/diagnostic from the service tech" etc etc... i mean, seriously? need to run diagnostic on what seems to be mechanical parts? does that make sense or is the vehicle that "technically advanced" LOL... (eg do you just want to charge me to run a diagnostic computer test)