Intermittent Squeeling

[naossoan]

Hi all,

So for the past couple years my Yaris would squeel when I started it up.

Pullies and belts etc look good and then I found this video of a guy with the same problem, and interestingly enough it would squeel exactly the same as mine if he put the key in and just started it really quickly.

But if he turned on the power, waited a moment, then started it, it wouldn't squeel.

So I tested this on mine and 9 times out of 10 if I start the car this way it does not squeel. If I start it quickly like he showed, it would squeel almost every time. Very strange.

Anyway, when it DOES squeel, if I turn the interior blower fan for the climate control OFF the squeeling goes away right away, whether the AC is on or not.

So I'm thinking it has something to do with the motor inside the dashboard for the climate control, as the squeeling noise does sound like it's coming from right in front of me somewhere in the dash, maybe passenger side.

Where is this fan and motor located so I can open the puppy up and look at/replace it? I took the glove box out to try to have a look but I don't see anything in there.

Anyone know? It's an 07 Yaris Hatchback.

[NYC-SE]

The blower motor has nothing to do with it, it is not driven by the belt. The alternator, however, is. The reason the squealing stops when you turn off the blower motor is because now the alternator is under less of a load and therefore the belt is less likely to slip and squeal.

[ex-x-fire]

Maybe starting it the first way has to do with the a/c compressor engaging while its trying to start. The 2nd way, maybe the a/c is already engaged.

[naossoan]

Maybe starting it the first way has to do with the a/c compressor engaging while its trying to start. The 2nd way, maybe the a/c is already engaged.

I'm not sure what you're saying. It would squeal sometimes whether the AC is engaged or not.


The blower motor has nothing to do with it, it is not driven by the belt. The alternator, however, is. The reason the squealing stops when you turn off the blower motor is because now the alternator is under less of a load and therefore the belt is less likely to slip and squeal.

Are you saying the alternator is bad, or the belt is bad? Or both? I should mention that the guy I previously mentioned claims he replaced the accessory belt and it was still squeal.

https://www.youtube.com/watch?v=HRrVMtyIqIY

I find it interesting the video is called "mystery solved" when he didn't actually solve anything. He just discovered it wouldn't squeal if he started it slowly lol. But it's exactly what's happening to me....

https://www.youtube.com/watch?v=6a0IeIE4qR4

[NYC-SE]

Are you saying the alternator is bad, or the belt is bad? Or both? I should mention that the guy I previously mentioned claims he replaced the accessory belt and it was still squeal.

No I doubt it is a problem with the alternator. More likely the belt is loose or worn. How old is the belt?

Or perhaps nothing is wrong at all. The squealing related to the speed of turning the key thing is real. Numerous people here have reported the same thing. I can even make it happen with my car as well and my belt is fine.

The guy in the video posits a computer - alternator communication issue as the cause. Perhaps he is right. I'm not sure of the reason but whatever it is the phenomenon is real.

[B.B._07]

It's been discussed here many many times, the solution to your problem is the belt needs to be tighten end of story. The Yaris does not have a auto tensioner for serpentine belt like the vast majority of modern cars do, so even a new belt will stretch after some time and the squeaking can come back. Mark the position on the tensioning bracket, and tighten in small increments until the noise is gone and you're done. Weather or not the increased alternator load theory is right or not is not relevant, it's making noise because there's not enough tension to keep the belt from slipping.

If you need some guy on Youtube to show you how, here you go:

https://www.youtube.com/watch?v=QMkNQULvH4I