Serpentine Belt Tensioner Replacement

Joined
Jan 10, 2005
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276
Had to replace the serpentine drive belt tensioner at 140,000 miles and used the following procedure.

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
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)
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)
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/
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
7. Remove passenger side timing belt cover; 3 bolts @ 10mm and 1 nut @ 10mm, release 2 hoses from keeper
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
9. Remove the serpentine belt tensioner; 2 nuts and 1 bolt at 10mm
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
 
Joined
Feb 25, 2005
Messages
158
 
jp. Excellent write up! :cheers: I was just in there doing the timing belt/water pump. Your instructions are clear and concise and look to be right!

I wrestled a bit with removing the fan/shroud. Any tips on removing those?

This post is a definite candidate for the faq.

Thanks,
Pete
 
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good writeup. based on the miles per year I put on my LC and I have the same replacement interval as you, I will be doing this in 12 years :)
 
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JP213a, nice job!
Did you notice any steering issues before the change? IE: if you hammer the throttle and try to turn real quick it makes it real hard to steer? I’m suspecting the tensioner to be the culprit with this problem. If the tensioner is not able to hold pressure on the belt then under acceleration the added load on the PS pump could cause the belt to slip.
Is the PS pump pulley near the tensioner by chance? If so I think this re-enforces my theory.
DMX
 
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DMX84 said:
Did you notice any steering issues before the change? IE: if you hammer the throttle and try to turn real quick it makes it real hard to steer? I’m suspecting the tensioner to be the culprit with this problem.
DMX
I had no steering issues with the old belt tensioner but never hammered the throttle while making a sharp turn. The belt travels over the tensioner, then the alternator, then the PS pumps. The pump pulley is about 4" in diameter and has over 90 degrees of belt wrap so there is good amount of contact area. That said, since Toyota changed the tensioner design and vendor source somewhere between 2000 and 2005, I suspect a "weak link" was discovered and corrected by the engineers. A weak tensioner spring could be the cause for your steering issue, especially if you're over 125k miles. Take a look at your tensioner while the engine is idling. If the tensioner pulley is continuely moving back and forth, the spring is weak. With the new tensioner, the pulley barely moves.
 
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if you are only replacing your Serpentine belt you really dont have to take the bottom cover off. I just loosened the tensioner and pulled up on the belt and slipped it off. Getting it back on was a bit trickier, but i had the schematics from Toyota on how the belt ran. If you and load the BT then you can slip everything into place very easily...
 
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Great post JP213a! it was very helpful. :clap:


I just had a tensioner pulley lock up and bust my serp belt. Here is my small contribution to the tensioner pulley info so hopefully no one else learns the hard way like it did.

I purchased an aftermarket pulley from Advanced Auto for my 2000 LX ($25 vs $109 at lexus...same pulley is only $87 at toyota tho). The part came from Dayco and was the only one their computer showed available. When you screw the bolt back into the tensioner assembly the concave washer that keeps dust and debris out of the bearings will not fit and rubs on the sides of the pulley. the OEM tapers towards the bearing, the aftermarket does not. dont waste your money on the aftermarket and it is cheaper at toyota than lexus for the same part.

 

scottm

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JP, how did you replace the bearing in the pulley at 125k? I found the lip on the back of the pulley covered the outer race, seemed like I'd risk damaging the pulley getting the bearing out. I have plenty of hydraulic presses and stuff to force it out, but I wouldn't know if I bent it slightly.

Great writeup, some of the timing belt writeups have pics that might help people to see what you're describing. I think I unbolted the power steering pump through the holes in the pulley, rather than take off the pulley, not sure if your year is different.

edit: Just noticed how old this thread is, JP hasn't posted in quite a while. Thanks Makulaf, I'd planned on replacing the pulley some day, probably would've had the same problem. After reading about the tensioner spring, I'll probably just order the whole assembly from cDan, maybe that's why I get belt chirping on cold days. I bet the stiff belt is bouncing the tensioner 'till it warms up.
 
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I know this is an old thread but I just replaced my idler and these instructions were invaluable...huge thanks to jp213a Thought it might be worth mentioning that on a '98 (136k miles btw) it is possible to replace the idler without removing the power steering pulley OR pump. It's tricky but you have just enough room to work the alternator out and let it hang. All in all the part cost about $60+shipping and took a little over an hour to swap.

About a month ago I replaced my steering rack because of a slight leak. The steering was definitely better after the swap but I was amazed that my steering got even noticeably better after I replaced my idler. The belt on the truck was about 6 months old, and the old idler was not jumping badly, etc. but as you can see from the pics the difference in the two OEM idlers is pretty significant (hard to tell from the pics but the housing that holds the spring on the new idler is maybe 40% bigger). If you're experiencing unusual resistance when parking for example and have the original old style idler I highly recommend replacing it before you do anything else.
Idler1.jpg
Idler2.jpg
 
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Sweet - I just ordered this part to swap it out during my tbelt replacement.
 
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Thanks for the write up. It made my life easy...

FWIW, on my 2000 LC, there is no way to remove the alternator without removing the power steering pulley.

I'd recommend checking the idler bearing next time you're under the hood. Simply use a 14mm wrench to unload the belt, and give it a spin. I wish I had. It could save you getting stranded.

photo.jpg
 
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I'm midstream on this, and have hit a road block...

Trying to figure out how to get the PS pulley off. Am I missing something... Like perhaps a bolt end to grab onto? See below...

image-408893651.jpg
 
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After looking at it long enough... Pushed forward with yanking whole PS pump off suspending with a bungee, and pushing forward from there.

Below also includes the serpentine belt that has what I think is about 80 or 90k on it.

image-3845478356.jpg


image-2293869497.jpg
 
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If the tensioner works, but only the pulley bearing is bad - you can just unbolt the pulley. It is left-hand thread - so it should unbolt clockwise. This will save hours of work.

The pulley with bearing is only a few dollars less than the entire tensioner unit, so I am ordering the unit. I have it off now so no extra work (timing belt change). My pulley spins freely, no drag (and a little noisy). I had a water pump leak and I think it 'steam cleaned' the grease out of the bearing.
 
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belt rub wire casing breach.jpg
pulley tensioner groove 1.jpg
pulley tensioner groove 2.jpg
wire breach box.jpg
[

Serp belt went out on wife's 2001 Lexus lx470 (~150K, 4th owners) saturday. I replaced it but when doing so noticed one of the pulleys in the belt circuit must be out of alignment because the belt is drifting inward on the pulley and wearing a groove in the pulley bracket (see picture). Any usual suspects that would go out of alignment? It is tough to get a good profile view and eyeball it. If belt alignment can be fixed, would you still replace the bracket since it has the groove (BTW, is this bracket the idler pulley tensioner?)

Also, the drifting belt wore into the casing of a wire powering the round black part with the red line/box. I wrapped the wire with electrical tape and tucked it behind a metal bracket where it seems it should be - back out of the belt path. This good enough? Would you relpace the wires?
 
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Thanks for this write up! I did this last night and fixed the squeaky tensioner pulley on my 2002 LX470 (216000 miles). I used a Toyota part considering the miles I got out of the original. Cost at local dealer was $83. It took me about three hours and I am fairly new to wrenching (although mechanically inclined).

A few comments:

For step 5, I used a Kobalt strap wrench. It worked well. I did have to use a long rachet for extra leverage on the pulley bolt.

Step 8 almost stumped me. I thought there would be no way to remove this piece. I did remove the stationary pulley just to the right of this for more room. The trick that worked for me was to go ahead and remove the serpentine belt tensioner bolts. That allowed me to slide the tensioner forward and back as needed to finagle the center timing belt cover out. When I reinstalled the tensioner I did not bolt it to allow for it to more forward as I worked the center cover back into place. This is definitely the hardest part of the entire job.

Step 9: My serpentine belt tensioner bolts were 12mm. All other bolt sizes were the same as listed.

Just a note: I suggest laying a towel over the fan shroud. I ended up scraping my inner arms a little on the back edge of the fan shroud. You don't notice it while you are working but notice it later.
 
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This part failed at 193K leaving me and my family on the side of the road. I had the truck towed home (over an hour away) and fixed it myself. If you haven't replaced the tensioner, then this is the day!!!! Just follow the jp213a instructions.

Big thanks to beno for the parts and advice!!
 

hoser

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Original tensioner? If not, then what was the age/mileage/brand of the one that failed?
 

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