Technical Service Bulletins

Abnormal Scion idler pulley noise

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Abnormal Scion idler pulley noise

Some 2008-2011 xB vehicles may exhibit an abnormal noise from the idler pulley bearing assembly. The idler pulley bearing, bracket and washers have been revised to address this condition.

Replacement of both idler pulley and bracket may be necessary on vehicles produced before the production change effective VIN JTLKE50E#81041289.

 Previous P/N                           Current P/N                      Part name

16603-28020                           16603-28050                    Pulley sub-assembly, idler

16631-28030                           16631-28031                    Bracket, idler pulley

If an abnormal noise is evident in the idler pulley, remove the drive belt. Remove the idler pulley bracket and pulley sub-assembly. Loosen the two bolts and remove the idler pulley bracket and pulley along with the two bolts.

Separate the idler pulley sub-assembly from the idler pulley bracket. Remove the idler pulley sub-assembly bolt and pulley.

Discard the washers on one or both sides of the idler pulley sub-assembly.

Measure the idler pulley bracket to determine if bracket replacement is needed. Place the idler pulley bracket on a flat surface and measure bracket height. The previous-version bracket measures 96.4mm high. The new updated bracket measures 94.8mm high. If the bracket height is measured at 96.4mm, replace it with the updated 94.8mm bracket.

Install the new idler pulley sub-assembly onto the idler pulley bracket with its center bolt. Tighten this bolt to a value of 44 ft.-lbf. (60 Nm).

Install the idler pulley bracket and idler pulley with the two bolts. Tighten these two bolts to a value of 37 ft.-lbf. (50 Nm).

Install the drive belt. Run the engine and confirm that the abnormal noise is no longer present.


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