front engine squeal

I've got a front engine squeal that I can't seem to find the cause. 2008 V6 Tacoma with 103,00 mile, well maintained . It sound like slipping serpentine belt. The car needs to be driven for almost an hour before it happens. I've replaced the serpentine belt, made sure I've got power steering fluid. More of a squeal than a whine, so I don't think it's the power steering pump but I'm thinking of flushing the fluid and look at the screen in the reservoir anyway. When I replaced the belt, the tensioner took a far amount of effort and seemed to move freely. Rotated all the idler pulleys and checked for wobble - none.

Only will do it when driving, not stationary. Usually happens when accelerating from a stop sign or traffic light until you get to around 30 mph with engine rpm at 1700 - 1900 RPM. Stops when engine is above 2000 RPM. Doesn't make any difference if AC is on or off.

None of my friends will ride under the hood while I'm driving, so it's a bit hard to pin down.

 

idler pulleys probably

 

Had my idler pulleys replaced for similar noise. Noise would come and go. One other source might be air conditioning clutch as documented on this site somewhere.

 

Thanks all. I think it is the idler pulley. To me, didn't sound like a power steering whine, so I decided to replace all the idler pulleys. Took off all 4 but napa only had 2 36173 and 1 36174, so I was missing a 2nd 36174. The tensioner uses 36174 although Toyota only sells the tensioner unit not just the pulley. It looks like the bad idler pulley was 36174 on the lower drivers side. The washer under the bolt was worn and distorted. In an earlier diagnostic, wasn't able to detect a problem by spinning any of the idler pulleys by hand with the serpentine belt off. So hopefully I'll get the remaining 36174 and in a few days see if my problem has been solved.

 

Let us know how that works out.

 

Agh!!!!!!!!!!!!!!

Well new serpentine belt, 4 new idle pulleys and still have the squeak. So now I'm going to flush the power steering fluid and try and look at the screen in the bottom of the reservoir to see if it's clogged.

 

I went thru this with another brand of Asian SUV. V-6 motor. Changed out everything that you've mentioned. Squeal continued.

Got in the vehicle to go home one day and the engine sounded like the Beverly Hill Billies going down the road.

The Harmonic Balancer had come apart. Part # 16371 in the picture. Listed as a "Fan Pulley"

http://www.villagetoyotaparts.com/s...=2012&ukey_category=19385&ukey_driveLine=6159

Not saying this is your problem - just something else to look into. Mine had about 240K-250K on it went it disintegrated.

 

Thanks for input. Throwing parts at it until the squeak goes away migtht be the only way to solve it. I did take the harmonic balancer off when the fan was off. Looked okay. And a new belt and idler pulleys at 100,00K + probably isn't all that bad, they didn't have too much life left in them.

 

Well, I flushed the power steering, steering did feel a bit more solid. Fluid was dirty but not as bad as some I've seen on YouTube. Got the noise after about a 30 mile trip, on the return 30 miles - no noise. And 2 shorter 10 mile trips - no noise. So I'm going to drive it a bit more until the sound gets easier to reproduce. Been looking at a Steelman wireless chasis ears that I might spring for to help diagnose the problem.

 

What did you torque the harmonic balancer bolt to when it was reinstalled? I'm assuming it was removed and reinstalled before this squeeling started or is my interpretation of the timeline wrong?

 

I took off the shroud and fan in order to replace the idler pulleys. So I developed the squeak and replaced the serpentine belt first and the squeak remained. Have no idea what the torgue was. In taking the fan off, the pulley turned when using a wrench. So I had to position the wrench horizontally, and place a wood block vertically on the wrench. Then I tapped the block with a hammer - a simple impact tool. To put it back on, I used the same technique. So the torgue is 2 or 3 hammer taps.

Maybe a question is - should taking the fan on/off with a wrench cause the harmonic balancer to slip on the belt. I've got plenty of force on the tightener determined by what it took me to untension the belt for replacement. And it moved freely. So I think the tightener is working correctly.

 

So the squeal was present before the factory torqued harmonic balancer bolt was touched? If so you can disregard my train of thought.

 

yup, the sequence was squeal, replace serpentine belt, replace 4 idler pulleys which required fan removal and harmonic balancer. will do a longer ride = 30 mile, 45 mins on tues and return towing my boat back from end of waterskiing. don't know if a towing load will make any difference but it's a new data point.

 

Well, the squeal is still there. The same symptoms, someplace in the front end, need to drive the car for around 30 miles or 45 mins or so before it happens. Right now I'm just going to monitor for awhile. When it gets worse, it should be easier to locate.