Intermitent Clutch (i think) Squeal

[alex22808]

Just took a look at the belt. It seems fine. I checked the grooved side and it fine ie the grooves were all there. it also felt pretty tight, so it seems unlikely that the squeal is caused by it being loose.

Is there any other options? i am no expert, but the belt seems fine to me. Again, thanks for the replies!

[CTScott]

Originally Posted by alex22808

Just took a look at the belt. It seems fine. I checked the grooved side and it fine ie the grooves were all there. it also felt pretty tight, so it seems unlikely that the squeal is caused by it being loose.

Is there any other options? i am no expert, but the belt seems fine to me. Again, thanks for the replies!

The happening most when it is cold/damp really points to the belt. The Yaris is tricky with belt tightening because it does not have a screw tension. Rather you have to pry the alternator away from the block and then tighten the bolt, so there is far less precision to tightening it than with a screw tensioner. Some brands of belts are better than others when it comes to squeaking. I have found that Dayco belts are the worst with the Yaris, where short of overtensioning the belt you can't make them stop squeaking (and that's when they are only a month or two old).

[alex22808]

Originally Posted by CTScott

The happening most when it is cold/damp really points to the belt. The Yaris is tricky with belt tightening because it does not have a screw tension. Rather you have to pry the alternator away from the block and then tighten the bolt, so there is far less precision to tightening it than with a screw tensioner. Some brands of belts are better than others when it comes to squeaking. I have found that Dayco belts are the worst with the Yaris, where short of overtensioning the belt you can't make them stop squeaking (and that's when they are only a month or two old).

In terms of checking the belt, what should i be looking for beyond the ribs being worn?

Also, there seems to be no tensioning device on the belt, unless it is on the underside. The belt just seems to fit round the 3 wheels and is tight just like that.

[CTScott]

Originally Posted by alex22808

In terms of checking the belt, what should i be looking for beyond the ribs being worn?

Also, there seems to be no tensioning device on the belt, unless it is on the underside. The belt just seems to fit round the 3 wheels and is tight just like that.

Look at the ribs for signs of them being shiny (called glazing of a belt). Also push against the long stretch of the belt. It should only deflect about 1 cm in the center of that stretch when pushing on it with one finger.

For tensioning, that is what I was saying above. The Yaris does not have a mechanism for easily doing so. You have to loosen the alternator bolts and then apply pressure against the alternator to move it away from the engine. While doing so you check the tension of the belt and once the deflection is OK, you tighten the alternator bolts while holding pressure on the alternator. When doing this a wooden hammer handle or something of that nature is what you use for leverage and you have to be careful not to crunch the oil control valve, which is mounted close to the alternator.

[tmontague]

I have used a long metal screwdriver, although wooden is ideal. Below is a picture of where the oil control valve is that you want to avoid. The first time I re installed a new belt I think I over tightened it as I wans't aware this was possible and cranked it. The belt didn't deflect much when I pushed on it so I loosened it due to fear of premature worn pulleys. A deflection os 1 cm is a good point to go with, I think there is a recommended amount in the manual somewhere.

Have you spilled anything on the belt recently? When the noise is happening open up the hood and see where it's coming from. If it's the belt it should e obvious. It is possible that the belt has worn a little and is now loose and just needs to be re tightened. If after being re tightened it squeals again then just install a new belt.



The above isn't the 1NZ-FE engine but its close and it has the sensor in the same position