Weird "30-second rule" when starting car stops belt squeal?

Hi everyone, this is my first post and I sought out a car forum because I have a question that so far, nobody in my real life world has been able to answer. I was hoping someone here might be able to.

It’s long but if you could persevere and read all the way through - my question is right at the end

I have a 2005 Toyota Kluger V6 that makes a horrendous squealing sound when I start it. This goes after a few seconds, unless I have the aircon on, in which case the squeal doesn’t stop. I did the “water spray” test on the drive belt and it eliminated the squeal temporarily. (The belt itself is less than a year old and the tension seems fine if a tiny bit soft.) This led me to believe that the pulleys may be misaligned and that the main culprit is the aircon compressor pulley.

The air conditioner on the driver’s side does not work – as in, it does not cool – and so for now we drive with the windows down. And of course there is the screaming whenever the aircon is on. It is summer where I live (Australia) and very, very hot. The other day I was on a call when I got into the car and so I turned the key in the ignition far enough to get the windows down while I finished the call, which was only about 30 seconds.

But then, when I then went to start the car, there was no squealing. At all.

This happens every time now - as long as I turn the key in the ignition first as far as it will go without starting the motor and wait about 30 seconds, there is no squeal at all when I start the car. Today, I wondered what would happen if I turned on the aircon while driving to see if the squeal started up like it usually does. It did - one shriek that cut off after a second or so and afterwards it was silent. That has never happened since the squeal has been a problem.

Can anyone explain this “30-second rule”? Why would turning the key in the ignition for a bit before starting the motor stop the squealing?

(Obviously, I will be getting the car fixed, but we can’t afford it at the moment as we’ve had a lot of other expenses. In the meantime, we only drive it when we absolutely have to.)

Thank you in advance :pray:

With the 3.0 L and 3.3 L engines it is common to have a belt squeal at start up if the belt is not tight enough. The belt may seem to be tight enough but it needs to be tighter.


Thank you! Do you have any idea why the “30-second rule” applies here though? Really, I’m just super curious about it as it seems to have the problem (at least temporarily) solved.

How do I actually go about tightening the belt myself? I am by no means a mechanic but I’m pretty handy and I reckon I could do it. If my dear old Dad were still with us he could have done it for sure, or showed me how.

I’m not sure whether it has an automatic tensioner or needs to be done manually.

I’ve never heard of any “30-second rule,” but I’ll venture a guess that it was the same guy who made up the “5-second rule…”

You know, “If you drop an item of food falls to the ground, for about the first 5 seconds, it’s safe to pick up and eat. After five seconds, the food is dirty, and you should throw it away.”

As for me, I’ll let that guy eat whatever he wants off the ground since I do not know how long it has been since they last cleaned up the dog poop…


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Ahahaha love it. It’s completely baffling to me - I just called it the 30-second rule because I found out by accident that it stops the squealing. I was just hoping someone could tell me why!

The 30 second rule, get in and get out… LOL



I was actually trying to write a funny follow-up to SaoirseL22’s reply when your’s came up, I cannot top it… I really got a good laugh, thank you!

As Yogi Berra said, “Why don’t you pair ‘em up in threes?”

And “When you come to the fork in the road, take it…”



I’m going to assume you’re on the young side. I am 64 and have been working on my own stuff since the early 70’s.

You mentioned money, a great way to save is doing your own maintenance.

Most modern cars have a “serpentine belt”. It’s much wider than the old “V” belts. With a SB they usually are tensioned with a spring tensioner. (The old V’s were usually manually adjusted).

Assuming you have a spring tensioner, I think you need to replace it. It is probably worn out. When the belt is off look very carefully at the pulleys. Make sure they look lined up and not loose in any way. Don’t chince out on the old belt, get a new one. It’s probably trashed from all the screeching. Go ahead and try it, you have to start somewhere, and this is a relatively easy project.

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Regrading the 30 second rule:

a decent guess (at least in my opinion, lol) is that in that 30 seconds of just key on, the cars computer is running and completing checks. It may be accomplishing some other tasks as well, that once these tasks are done- the pull on the charging system (read: Alternator and pulley,) isn’t enough for the loose belt to squeal upon starting.
but when starting immediately, you are putting extra strain on the charging system with the starting, tests, tasks, etc all happening at once.

Replace the belt and tensioner and see if it all goes away. When the belt is off, had spin all the pulleys (except the crank pulley,) and verify they all spin freely and don’t have any side/side or up/down motion to them.

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Thank you so much, that’s really helpful. I just went out and spent a good 30 minutes looking at things. I re-checked the belt tension and it’s definitely ok - it’s not too loose, I can’t get more than half an inch of movement in it even if I push pretty hard. It’s also only 10 months old and there is no fraying or any other signs of wear. I’m a bit loathe to replace a belt that’s virtually new but obviously if I need to I will.

The screech has all but stopped completely unless I start the car completely cold and then it’s soo loud but it does go away once driving. Today, I had things humming along nicely, I can’t see any wobble but a more experienced eye would be able to tell.

But the screech is DEFINITELY related to the air conditioner - when I put it on while the engine is running it screams the place down. There are also two belts - the wider one that goes around the alternator, A/C compressor pulley, water pump pulley etc and then a shorter, thinner one tucked in on the inside of the crankshaft pulley. And that’s pretty much where my knowledge ends. I don’t even know if I’ve got all my pulleys named correctly haha.

I will take a photo as well as try to upload a video of it so that someone else with a lot more knowledge than me can see what they think.

Glasspilot - I was born in the mid-70s but I like to think of myself as young!! :joy:

You are young, my first child was born in 76.

It is possible the bearings in the A/C clutch pulley are going bad

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The belt is loose. That belt needs to be tight or it will squeal, deflection should be no more than 1/8".

I could be wrong, but OP said he had 2 belts. one wider one which I am guessing is a serpentine belt. if so he should have a tensioner which should adjust it to the correct tension. I am not familiar with his vehicle so he might have one that you have to manually adjust. but either way I think he should change the belt if it has been squealing, even though it is fairly new. a belt can wear quickly if it has been slipping.

Thank you :pray:

(And actually the OP is a she … :blush:)

Ok, here is a photo of the belts. Do the edges of the belt actually look a bit frayed or is it my imagination? IRL they look fine.

There is also a video - A/C is on when the car starts but, goddammit, the screech doesn’t last cos I put WD40 on it haha.

Still, I turn it off (the A/C) and turn it on again but the squeal actually doesn’t come back. Sigh.

Also, the A/C on the driver’s side doesn’t work - it blows but it doesn’t cool. Not like the passenger side, anyway. But that predated even the new belt.

I can’t upload the video so here is a link to it :+1:

sorry about that. I am not familiar with your vehicle. but the edges look slightly worn. that could be caused if the pulley bearing on the tensioner is worn and giving an ever so slight wobble. have you ever changed it? If not, I would change it and the idler pulley along with the belt. when you put the a/c on it does put a little more strain on the belt which if the belt is not tight enough can cause it to slip. your belt has been probably slipping causing the squeal. even though it is only 10 months old it should be changed again for that reason. I am not a pro. mechanic, but I believe there should be no more than about a quarter inch of up and down movement in the belt when tightening it. also, so you know, years ago one of the ways you could tell if a belt was bad is if it had a lot of cracking on the belt grooves. that is not so now with the new belt technology.
If by some chance you are from Australia, (most of us here are in the US)
I have found this that you should be aware of for your vehicle…

2004-2005 Toyota Avalon, Camry V6, Kluger, Lexus ES 300, RX 330 recalled in Australia: 24,222 vehicles affected - Drive

These belts do not operate in a serpentine configuration, there are no idler or tensioner pulleys Toyota refers to these as drive belts.

Belt adjustment shown below.


thanks Nevada. I stand corrected

I am from Australia!

Thank you so much for your input and advice :pray: