Serpentine Belt Tensioner Replacement (2 Viewers)

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Bit of a question changed my belts 25000 moles ago sometimes on start up hearing a screeching sound belts look fine and tension could it be bearings ?.Thanks.
 
This thread is great. Got my tensioner swapped out in my 2000 LX470. It took me about 2-2.5 hours (mainly because I’m slow!) Really not a difficult job.

As others have said, you really don’t have to remove the ps pulley, at least not on a 2000. If you can insert a socket wrench through the pulley to loosen the mounting bolts, just do that. It’s very quick. Also, you don’t have to fully remove the drivers side timing cover. Just pull it out enough to get the center cover off.

At the end it turned out my alternator pulley was damaged I’m not sure how that happened but the new tensioner was chattering and shaking at start up. Turned out the alternator pulley was the culprit. The one side was pushed in and swishing the belt. I recently swapped it out with a Denso one. Who knows!!!????? I’ll swap out the pulley tomorrow. I bent it into submission to get me to work today.

Thanks for the great write up and comments from all
 
JP213a and others, thanks a million for this thread! Tremendous help when my belt broke off (2001 LC with 177k miles) and I had to work on this during the weekend. I got lucky with the power steering pump pulley and I didn't have to touch it at all. I was able to navigate the alternator and was able to access/remove tensioner pulley.

I'm more of a visual learner so, I took JP213a instructions and added some images below. While I took some different route in some steps, overall it was perfect, I hope it finds it helpful for others who are like me (who are not mechanically savvy).

Serpentine Belt Tensioner Replacement

1. Remove front belly pan (engine under cover); 8 bolts @ 12mm, recessed bolt is machine thread, others are self tapping
2. Remove engine V-bank cover; 2 bolts & 2 nuts @10mm, release 1 hose from keeper at rear corner on driver’s side
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3. Remove intake air connector/box; 2 bolts @10mm, 2 hose clamps @ 10mm, disconnect 4 small hoses, pull big tube off throttle body then lift up intake air connector and pull tube off air filter outlet (air mass meter stays with air filter)

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4. Remove serpentine belt; release belt tension with 14mm socket on tensioner pulley bolt with racket set to loosen (tensioner bolt is left hand thread)
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5. Remove pulley from power steering pump; 17mm nut with box end wrench, hold pulley with homemade holding tool (see below) or strap wrench or Toyota’s special service tool (SST) 09960-10010 Variable Pin Wrench available at http://toyota.spx.com/

Can't add more images, so to the next thread...
 
6. Remove alternator securing nut and bolt (don’t disconnect electrical connection); 14 mm nut and 14mm bolt, slide alternator forward off stud and let it hang

udublf: I was able to remove the top bolt and just loosen the lower alternator bolt to tilt/pivot the alternator enough to the left to slide in/out the tensioner pulley. I do have a replaced alternator so not sure if that's the reason why I didn't have to remove the whole alternator assembly.
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7. Remove passenger side timing belt cover; 3 bolts @ 10mm and 1 nut @ 10mm, release 2 hoses from keeper
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8. Remove small center timing belt cover; 2 bolts @ 12mm; it is tricky to work the cover out of the tight space below the cooling water pipe and even trickier to work it back in
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9. Remove the serpentine belt tensioner; 2 nuts and 1 bolt at 10mm
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10. Assembly is the reverse order except position the center timing belt cover under the cooling water pipe before installing the tensioner



Power Steering Pump Pulley Holding Tool Description (homemade):

Take a piece of steel bar stock 16” long x 1” wide x ¼” thick. Drill a ½” hold in ¾” from one end. Drill a second ½” hole three inches over from the first hole. Insert a 7/16 x 1 ½” or longer bolt in each hole and screw a nut on to each. Run the nuts down to the bar. The two bolt ends fit into the holes in the power steering pump pulley face. Hold the bar stationary while loosening the pulley nut with a 17mm box end wrench. A piece of Unistrut could be substituted for the steel bar www.unistrut.com

Notes:

1. Tensioner is Part No.16620-0W100; List $71.73; Wholesale $57.38 (the tensioner comes with the pulley as one unit)
2. The new tensioner was made in the USA and the original equipment was
made in Canada by Litens Automotive Group, model 4-121.
3. The new tensioner has a slightly different design, primarily the spring
4. The tensioner was replaced at 139,918 miles.
5. The bearing in the original tensioner pulley was replaced at approximately 125,000 miles (bearing number 6203 by NSK) due to a rough spot. The replacement bearing had a rough spot and a screech at 139,918 miles. The bearing seal was removed and it was dry (no grease).
6. The tensioner spring in the OE tensioner was weak. The pulley was bouncing when the engine was idling, causing the drive belt to chirp. With the new tensioner, the pulley was stable and the chirp was gone.
7. A serpentine belt routing diagram is located on the bottom side of the hood, passenger side
8. Instructions assume a left-hand drive
9. Bolt and nut sizes given are head sizes
 
Nice write up for tensioner replacement..

For future reference, if tensioner is good (good strong spring pull back). Then we just change bearing, by pressing out and in a new bearing. Skid plate and air pipe can remain in place. Cost ~$15, time ~30 minutes.
 
So my serpentine belt fell off for the first time last Saturday. I was able to get it back on and drive the vehicle back to the house. No further issues were encountered that evening. I went out to start the vehicle this morning and the belt came off the pulleys immediately upon start up. Didn't have time to mess with it then and came back to it this afternoon. Three more tries and the belt came off upon ignition every time. The tensioner indicator is on the last of the marks for the "good" range (bottom right of photo). Without someone else to turn the ignition while I watch what is going on I am not sure what is causing this, but I am leaning towards the tensioner being the issue. Has anyone else experienced this issue? Any help would be appreciated.

IMG_6809.jpg
 
Assuming you've a good Toyota OEM belt and all the pulley bearings are good. The likely cause is the tensioner has little to no spring tensioner remaining. It's shot!

Very easy to determine. Using a 14mm socket with socket wrench or breaker bar. Turn the nut that retains the tensioner pulley CCW, just as you do when removing or installing the drive belt. You should feel a lot of spring force feed back.
 
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Well, replaced the tensioner, idler pulley and put a brand spanking new toyota belt on the LX. Threw the belt upon ignition. Put it all back together again and went through all pulleys and connections. Saw that the compressor was wiggling when the tensioner was pulled over to install the belt. Climbed under the vehicle and found a missing bolt in the AC compressor. I tightened up the bolt that was left and have ordered the replacement bolt. FSM shows 3 bolts in the compressor, but all other diagrams that I can find (including the parts catalog I have for my model year only show 2. If there is a 3rd it is so buried under all the hoses and stuff in the DS of the engine that I cannot see it. Hopefully the bolt will solve the issue once it arrives. Very frustrating.

The guide with photos above by @udubfl was excellent. Two other items to add, though. 1) In step 9 the nut and bolt on my vehicle were 12 MM, not 10 MM. Might be a year thing. Mine is a '98 LX. 2) I found pulling the tensioner out of the way really helped get the small center timing belt cover out and back on. I did have the stud that the nut on the large timing belt cover screws on to come off with the cover. Beware just in case this happens to you.
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Ooh, those could be the hated bolts involved in a timing belt change. They bolt the ac compressor to the fan bracket, and removing the oil filter is pretty much necessary to get to the back one. It’s possible on a timing belt swap, someone didn’t properly tighten yours or loc-tite it, which is why it backed out. It is near impossible to get a torque wrench on it. Hopefully the threads are good where the bolts go in. If not, then it may be time to swap the fan bracket, which is basically a major portion of a timing belt change.
 
AC compressors all have 3 bolts.
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Looking at PN diagrams, notice they list 2 of the same PN # for lower which is same length as rear.
The front upper has different PN #, IIRC is longer one.
 
I ordered two like the parts catalog said and the top bolt (different PN). That back one will be a hell of a bolt to get in. Not looking forward to it. I will be slathering it in loctite for sure!
 
They don't fall out if torqued and torque is not that much. I'd not use loctite. In fact I use a little anti seize. Really not to bad unless bolts threads are dry. This is steel going into aluminium on fronts. Someone just likely forgot to tighten during timing belt or fan bracket job. You may find rear is accessible from wheel well "IDRC". I don't usually touch the rear bolt, while doing t-belt or just fan bracket.

The fronts upper I get to from up top, from within engine bay.

The lower front I come at from below.
Remove your oil filter makes even easier.

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I also come in next to steering rack boot.
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I ordered two like the parts catalog said and the top bolt (different PN).
Look again at parts diagram. Notice one bolt PN# 90099-04421 (2). The (2) denotes two of these bolt required. Three bolts, one is different than other two..
 
Guess I will rethink the loctite. Thank you for the advice. I always enjoy your posts. The photos are always great. I ordered all three of the bolts this morning. Hopefully I’ll be able to tackle this next weekend.
 
Your welcome!.

You may find working from top difficult with fan, shroud, hose, etc in the way. Try going at top bolt, from bottom with skid off if you do. But don't fight it. Sometimes the long road will save time. Meaning, get stuff in the way out of the way.

You'll see it no big deal, really.

I find so much shop mess up I've, lost track. I just deal with it.
 
Thanks to all for the amazing collection of information on the serpentine belt change etc. We had rattling & squealing from the belt, and figured it was likely the tensioner pulley assembly was culprit. Ordered Toyota tensioner kit and followed the instructions for disassembly on this thread.

FWIW, when we finally got the belt off, it was clear the bearings were shot in the tensioner pulley. Pressure from the tensioner was good, and we struggled with whether to proceed with replacing everything or simply the pulley from new kit plus new belt onto the existing tensioner body. Long story short, we decided to simply remove pulley from new kit & replaced it on old tensioner body, then installed new belt. It's been nice & quiet since.

Just sharing that it might not be necessary to go all the way with more disassembly work. We will wait till the Timing Belt service interval to do everything together when it comes. Hope this is helpful info
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for someone out there :)

Side note : You can replace the bearing on pulley with NSK6203ZZ bearing.

 
Thanks to all who contributed to this thread. I just replaced the tensioner+pulley. It took about an hour and a half.

You absolutely do not need to remove the front skid plate or the PS pump pulley.

The center timing cover was a huge annoyance, just like everyone has mentioned. It’s like a terrible jigsaw puzzle piece that you have to figure out the secret to removing and installing. Pay attention when removing it, it will help during reinstallation.

If you remove the three PS pump bolts and two alternator bolts, you can just kinda push everything an inch out of the way. Also, it seemed like my original tensioner was OK at 180k, but when I spun the pulley by hand, it had that gritty, free-wheeling, classic worn out bearing sound.
 
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I've got the squealing from this area. First started on cold and wet days when the engine was idling after startup. No need to turn the wheel, and turning the wheel makes no difference in the sound. Disappears after the truck warms up. (2006 LX, 160k)

Went away for a while, then during a warm spell (60 degrees) last week after sitting for a few days, really loud, and it took longer than usual to go away.

I've had a stethoscope down in there and can't find the source of it near the pulleys or tensioner.

I've got a new tensioner and belt, but before I throw that on (-1 Fahrenheit as I type this so not happening this a.m. :) ), can anyone provide some advice about where to aim the stethoscope for diagnosing what it is likely to be squealing?
 

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