Serpentine Belt Tensioner Replacement

[jp213a]

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

[skopiec]

Wow - great write up! I'm sure others will benefit from your detail...

[ppressle]

jp. Excellent write up! 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

[SWUtah]

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

[DMX84]

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

[jp213a]

Originally Posted by DMX84

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.