DIY $2 Serpentine Belt Tool, Belt lengths & Routing

MVS Forums member QuirkySwede offers up a challenger to the hotly-contested World’s Cheapest Serpentine Belt Tool Trophy™ (see my own 75¢ job). Plus he sheds some light on serpentine belt routing theory and practice.

Notice how Volvo first changed routing to improve grip on the alternator, and later (bottom right) routing regained grip on the A/C reducing the chance of squealing when activated on those 100° F summer days, though that belts backside then runs on the alternator. Other variations may encountered so always check and note routing before removal. One can switch from the “early” to to the “late” setup provided you use the longer belt. Both the picture and table are just to illustrate differences, not a guide for what your particular car should have.

Serpentine Belt Length Comparison

Best way to know what best to replace your belt with is measuring the old one and looking for numbering on it. This will provide a rough idea of what was used on which models and when, but verify before purchasing.

125.3cm (49.3″) without air conditioning: 9146844, 9146117, 115286, 21.0002, 21.0003, 6PK1256, 6PK1250; 1991-1997 850 w/o A/C, 1997-2005 C70 w/o A/C, 1996-2000 S70 w/o A/C, 1996-1998 S90 w/o A/C, 1996-2000 V70 w/o A/C, 1996-1998 V90 w/o A/C
174.3cm (68.5″): 9186352, 88986809, 94829, 48401, 6PK1743, 5060685, 685K6; 1993-1997 850**, 1998 C70, 1998 S70, 1998 V70
175.2cm (69″): 9458411, 15478, 6PK1755, 6PK1750, 690K6, 685K6; 1997-1998 S90, 1997-1998 V90, 1995**-1997** 960
182.5cm (71.85″): 9458469, 8692141, 30731811, 94824, 6DPK1825; 1999 S70, 1999* S80
184.2cm (72.5″): 9471981, 1841, 30731808, 9471799, 9458376, 124703, 6060724; 1999 C70, 1999-2001 S70, 1999-2006* V70, 1999*-2006 S80, 2000-2003 S40, 2000-2004 V40, 2001-2006* S60, 2003-2006* XC70, 2003-2006* XC90
185.3cm (73″): 9497241, 8627228, 30731809, 6PDK1853, 124709, 15502; 2000-2004 C70, 2000 S70, 2000 V70

* Check Chassis Number
** Use Late Routing (Alt.-Idle-P.S., not A/C-Idle-Alt)
TIP: The belt’s length and rib count is often incorporated into aftermarket belts’ number:
6PK1755 = 6 ribs 1755mm long
690K6 = 69.0″ 6 ribs.