squealing noise when start cold

[stoney]

Hi All,
My 3rd gen 4runner recently has squealing noise about 1 second when starts cold in the morning. I search on this forum and found out it might be the drive belts (air compressor belt or alternator belt).
I have turned off the a/c when starting the car but the squealing noise is still there.
I also noticed that when the A/C is off, the a/c compressor belt is still moving. Is this normal? Is there a way to turn the a/c compressor pulley off when starting engine?
Thanks,

--stoney

 

[mtbtim]

Your AC is always turning but that doesn't mean the AC is always running. When you turn on your AC, a clutch engages and then starts powering the AC compressor. One of your belts is loose. Grab midway between two pulleys on each belt and check the deflection. Deflection is how far you can push or pull the belt from it's straight line. 1/2 to 3/4" is about the right amount of deflection. So, check your AC belt, Power Steering belt and Alternator belt. You most likely will find one or more of them too loose.

 

[VernySanders]

In addition to what Tim said, one of my drive belts wasnt loose but actually was very old and when i took it off to replace with new ones it was partially split and all I can assume is that what was creating the noise.

 

[stoney]

Thanks for all the replies. As for pulling or pushing the belts, how much force should be used? Is it better to use a tension measure? What is the spec'ed tensions of all the 3 belts?

--stoney

 

[mtbtim]

Thanks for all the replies. As for pulling or pushing the belts, how much force should be used? Is it better to use a tension measure? What is the spec'ed tensions of all the 3 belts?

--stoney

Hey Stoney, like the name by the way.

When checking for deflection, you're just using mild to moderate amount of force with your hand and arm, basically extending and retracting your arm at the elbow. You're not putting your body weight into it.

A belt tension gauge is a nice tool to have. The one I bought is a little pricey but there are more affordable option out there. In the video description we provide a link to the belt tension gauge I bought.

This video that [MENTION=102606]infamousRNR[/MENTION] and I made has all the belt tension values in it and it will show you how to go about tightening any of the belts that need it.

<iframe width="560" height="315" src="https://www.youtube.com/embed/Zi1XfFUOjKc" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

 

[BoomerBob]

Thanks for all the replies. As for pulling or pushing the belts, how much force should be used? Is it better to use a tension measure? What is the spec'ed tensions of all the 3 belts?

--stoney

In addition to all the good input so far; the compressor has two sets of bearings. One in the pulley the belt rides on and a set inside the compressor when the clutch engages. If the belt isn't the issue, and hopefully it is, it could be the pulley bearing starting to go out with this noise being a warning. How many miles on the vehicle?

As far as tension goes; you have two other belts to compare it to assuming they are adjusted correctly. I like to see a half inch of deflection both ways at the middle of the belt but that's just me. That might be a little loose for some belts depending on their length.

 

[stoney]

Hi Tim,
Thanks for the video with all the details. It is very helpful. BTW, is it difficult to remove the front skid plate? Do you have any instruction about how to remove it.

@Bob,
My 4runner has about 170K miles.

--stoney

 

[mtbtim]

Hi Tim,
Thanks for the video with all the details. It is very helpful. BTW, is it difficult to remove the front skid plate? Do you have any instruction about how to remove it.

@Bob,
My 4runner has about 170K miles.

--stoney

It's really easy to remove and it's not that heavy. It's held onto the bottom of the vehicle with (5) 12mm bolts, 3 in the front and 2 near the rear of the skid. The two in the rear are recessed and harder to see but if you have a headlamp or other source of light, you'll see where they are. There's also 2 more bolts that attach the front skid to the rear skid and you'll need to disconnect those as well. I usually just go ahead and take off the rear skid first and then take the front one off. To get the rear skid off, you just have to get two more bolts out that secure the rear of the skid to the vehicle. So, 9 bolts in all. Getting them back on, I put the front skid on first, and then with the front skid bolts still loose, I get the rear skid on and connected to the front skid. Once all the bolts are started, I start tightening them all up.

In this video https://www.youtube.com/watch?v=2nVbwe2t2T8&feature=youtu.be watch from play time 9:02 to 10:26 and you'll get a good idea of how to get the skid plates disconnected from the your rig.

 

[phattyduck]

Your AC is always turning but that doesn't mean the AC is always running. When you turn on your AC, a clutch engages and then starts powering the AC compressor. One of your belts is loose. Grab midway between two pulleys on each belt and check the deflection. Deflection is how far you can push or pull the belt from it's straight line. 1/2 to 3/4" is about the right amount of deflection. So, check your AC belt, Power Steering belt and Alternator belt. You most likely will find one or more of them too loose.

All true stuff, but as a note, if the HVAC system is set in either of the defrost modes, the AC compressor will run even with the AC light off.

If the belts are fairly tight and still make noise, they may just be old/glazed and not able to grip the pulleys.

-Charlie

 

[TheDurk]

Thanks for all the replies. As for pulling or pushing the belts, how much force should be used? Is it better to use a tension measure? What is the spec'ed tensions of all the 3 belts?

--stoney

I have the tool, but, honestly I don't use it. Your A/C is not the issue, because it definitely would only squeal, or squeal a lot more, when compressor is called. So use that as a guide to check the other two.

Recognize that no amount of tension will stop an old belt from squealing. 100k or so and they are due to be changed.

I'd say a half inch is too much. More like 3/8" or a tad less. Check new belts after a few weeks.

 

[stoney]

Tim,
Thanks. You are the man. I just notice that you are in Bay Area. Maybe I should let you fix my car for your next Youtube video ... LOL.
This week the weather is much warm and there is no 1 second squealing noise in the morning when I start my car.

--Stoney

It's really easy to remove and it's not that heavy. It's held onto the bottom of the vehicle with (5) 12mm bolts, 3 in the front and 2 near the rear of the skid. The two in the rear are recessed and harder to see but if you have a headlamp or other source of light, you'll see where they are. There's also 2 more bolts that attach the front skid to the rear skid and you'll need to disconnect those as well. I usually just go ahead and take off the rear skid first and then take the front one off. To get the rear skid off, you just have to get two more bolts out that secure the rear of the skid to the vehicle. So, 9 bolts in all. Getting them back on, I put the front skid on first, and then with the front skid bolts still loose, I get the rear skid on and connected to the front skid. Once all the bolts are started, I start tightening them all up.

In this video https://www.youtube.com/watch?v=2nVbwe2t2T8&feature=youtu.be watch from play time 9:02 to 10:26 and you'll get a good idea of how to get the skid plates disconnected from the your rig.

 

[mtbtim]

Tim,
Thanks. You are the man. I just notice that you are in Bay Area. Maybe I should let you fix my car for your next Youtube video ... LOL.
This week the weather is much warm and there is no 1 second squealing noise in the morning when I start my car.

--Stoney

Well, if the squealing returns, I'm sure you can handle doing this on your own. If you take up the challenge of turning wrenches you'll learn a valuable skill and you'll save tons of money in the process. You might end up with a tool buying addiction like I have, but the good thing is the money you're saving doing your own work will pay for the tools with money left over to boot.

 

[willco]

Hey all,
I'm getting the same thing on my 2000, but wonder if it is idler or tensioner pulley bearing? 2-3 seconds after cold ignition (below 40 degrees), it starts and lasts for 10-30 seconds depending on temp. Won't do it again until off for 1hr or so. Tried dielectric grease everywhere, no improvement. How to diagnose best? Belts seem like correct deflection, unsure how old. Bought the lower tensioner pulley (grooved), but now not sure that's it, and since it's winter and I have to pay to get it in the air, want to fix it first time. Thanks for any thoughts.

 

[The Cold War Kid]

Speaking of tools, a piece of heater hose about 3 feet long is invaluable. Put one end next to an ear. Move the other end around the places a sound may originate...

 

[phattyduck]

Hey all,
I'm getting the same thing on my 2000, but wonder if it is idler or tensioner pulley bearing? 2-3 seconds after cold ignition (below 40 degrees), it starts and lasts for 10-30 seconds depending on temp. Won't do it again until off for 1hr or so. Tried dielectric grease everywhere, no improvement. How to diagnose best? Belts seem like correct deflection, unsure how old. Bought the lower tensioner pulley (grooved), but now not sure that's it, and since it's winter and I have to pay to get it in the air, want to fix it first time. Thanks for any thoughts.

The tensioners are generally pretty good. Just get 3 new belts and install. Sometimes old belts will still slip/squeal even with the correct tension.

-Charlie

 

[Hopeless Diamond]

I have this too on my '96. Belts are all new and tight, new idler in A/C. Maybe idler on timing belt?

Or, as I prefer to believe - It's just squealing with excitement that its getting to go for a ride :girl:

 

[brillo_76]

When it gets real cold. You may a clunk or a 1 second loud moan out of them too. Most Toyotas will do that as I never did discover the cause.

Sent from my SM-J337V using Tapatalk

 

[willco]

The tensioners are generally pretty good. Just get 3 new belts and install. Sometimes old belts will still slip/squeal even with the correct tension.

-Charlie

Thanks for the response Charlie. I assumed that if it were a belt, it would be more constant or frequent. Does sound like coming from lower tensioner. Belts on hand when it's in the air is probably a good idea though. Thanks.

 

[shadow247]

My 3rd Gen has done this on and off since I got it with 341k. I put an Aisin timing belt kit on it about 2 years ago. My thought is the seal on the upper timing cover is bad, letting moisture condense on the timing belt. It never does it cold dry days, only days when the dewpoint is high enough to really leave the outside of the truck soaking wet. I'm certain it's not the main belts, because I removed all the belts and the noise remained. Since it's such a rare issue, I just haven't worried about it. I plan to replace the upper timing cover seal when I put on the Valve Cover Gaskets early next year.