What the hell is this noise!?

[Thorgan112]

so for the last month or so, when I start up my 4Runner I get a loud squealing noise from the engine for about 30 seconds or so and then its gone. I had my timing belt done about a year ago. Any suggestions on what to check? I was thinking it may be the timing belt slipping and was hoping it just needs to be adjusted and tightened a bit, but to be honest I have no idea if a loose timing belt would cuase a squeal... any advice? And yes, I know, asking to diagnose a "sound" over the internet is practically impossible. just looking for some thoughts

 

[Joelev]

Run down to Harbor Freight and get one of those mechanic's stethoscopes if it's not obvious after you put the hood up and take a look.

I'm down in Ft. Greene if you want a second set of ears.

 

[JayRolla]

Sounds like a drive belt. The timing belt is a major component of the motor that does not slip. It has teeth and if it slips timing goes off and motor run really rough.

You have a loose and or bad alt, power steering belt or some other. These are the belts you can see. U cant see timing belt since its behind a cover. If the sounds changes and goes away with revving then most likely a belt.

 

[Thorgan112]

Run down to Harbor Freight and get one of those mechanic's stethoscopes if it's not obvious after you put the hood up and take a look.

I'm down in Ft. Greene if you want a second set of ears.

I may take you up on that offer

Sounds like a drive belt. The timing belt is a major component of the motor that does not slip. It has teeth and if it slips timing goes off and motor run really rough.

You have a loose and or bad alt, power steering belt or some other. These are the belts you can see. U cant see timing belt since its behind a cover. If the sounds changes and goes away with revving then most likely a belt.

thanks, that helps a alot now, at least I know it is most likely not the timing belt then. I am gonna take a look at the alternator belt, its still the original one, so that may be the culprit

 

[hearno]

thanks, that helps a alot now, at least I know it is most likely not the timing belt then. I am gonna take a look at the alternator belt, its still the original one, so that may be the culprit

Timing belts don't squeal when they slip. They don't really slip either. They have large teeth in them and they can jump but not slip. Were that to happen, you'd be asking why your truck doesn't run at all. It is most likely a drive belt as indicated above.

 

[animator]

Most definitely a drive belt. It is easy to not get the tension set correctly on those belts. It may "feel" correct, but still squeel a bit. If it squeels only on startup, it could be any of them. If it squeels with the wheels turned, it is the PS belt. If it squeels only when the AC system is on, it's the AC belt.


There is a lot of info on how to properly tighten the belts, so searching should bring it up.

 

[Unner]

I would say it is one of the belts or possibly a bad pulley for one of the belts up front. Definitely not the timing belt though.

 

[Drcoffee]

start the engine cold and squirt some WD40 on each belt one at a time. The one that quiets down is the offending belt/pulley. Its very easy to do. just avoid the fan blades.

 

[T4R2014]

Sounds like drive belts. Only use OEM or Bando when replacing them. I have some Gates brand ones on mine and they will squeal for a few seconds if it is a very rainy day for some reason. The are only a few years old. By comparison, my OEM's were squeal-free for 15 years.

 

[Joelev]

I may take you up on that offer

I've got basic tools and such, too, if you want to take a crack at DIY. And lots of free parking under the BQE. :smow: