2.5 Gen with loud whining noise from engine

I just sold my 16 TRD Pro because I wanted another Platinum. I’ve owned 5 5.7 Tundras. I went to test drive a 2016 Platinum last night with 120k miles. Immediately upon start up it sounded different than any of my other 5.7s. The engine ran smooth. No lights on but it had a loud supercharger like whine. So much so that I opened the hood to make sure it wasn’t supercharged. It appeared to be coming from the right passenger side of the engine. I have a video but it wouldn’t let me upload it.

 

Check the passenger seat for my ex.

 

Did you check that the air filter was properly seated and the airbox lid was on properly?

 

I did not but I will. It had just been to the dealer for servicing in the last week.

 

Did it change with engine speed ??

 

maybe some aftermarket air filter/TB spacer etc..

 

It didn’t necessarily get louder but it was there at start up and was present the entire time driving around 6 miles and when I parked it I raised the hood because it was still present. Outside temp was mid 50s so it wasn’t cold out.

 

Probably an idler pulley or tensioner pulley on the serpentine belt, but could be any of the belt-driven components.

 

That is where I would start..

 

Might be the alternator... Took me a while to pinpoint, but once sure, I replaced alternator and whine stopped. Used a 2' piece of PEX pipe to act as stethoscope. Replacement was a PIA, but doable from passenger side wheel well. Initially whine was most noticeable at cold start, but after a couple of years you could hear it all of the time. I thought it was a pulley at first, but the PEX pipe led me to the alternator.

 

Sounds like a bearing, tensioner, etc. When one of those parts that spin start going bad, it can have that whine sound, so alternator, tensioners, check anything that has a bearing or spins in the engine compartment. Power steering will also make a similar noise if pump is dying.

 

Same experience on my 2017. I really didn't mind the sound, just knew that it would end up badly when the bearing finally went. I only had 35K miles on the truck when it happened. Thankfully the dealer replaced the alternator at no charge.

 

Mine has been making a whining noise for about a month now. Started out of nowhere and it is most noticeable right when I start my truck and then less once it’s warmed up but it’s always there even at idle and more so when starting to accelerate from a stop. It follows engine speed and rpm’s while shifting, not vehicle speed. My first check was power steering fluid level as my old 4runner had a power steering fluid leak and the sound is almost identical to that of the power steering pump when low on fluid. No leaks and fluid level is normal on the Tundra. It sounds like it’s from the general area of the alternator, water pump or power steering pump though. Does this sound like the same symptoms that those of you have fixed by replacing the alternator?

 

It definitely sounds like it could be the alternator. Amazing how much it sounds like a power steering pump with issues. Now my 2015 Tacoma is giving me the same sound as the Tundra once did. Haven’t done the pipe trick yet to determine exactly where the sound is coming from, but my guess is the alternator.

 

Update: I finally found the time and bought myself a brand new alternator from the dealership, spent about 4 hours on my day off swapping it out along with a new serpentine belt since I had to take that off anyways and couldn’t have been happier when I fired it up and could actually hear my engine and exhaust at idle instead of noisy whining alternator that was definitely the culprit!