{
    "lazyNodes": false,
    "abFitnotesFlag": false,
    "abCrawlReviews": true,
    "productOptionsCookie": false,
    "orderDelayFlag": false,
    "skipSessionCookie": false,
    "covidMessage": false,
    "fullTitleCookie": false,
    "nrLoggerCookie": true,
    "checkoutReviewCookie": false,
    "productOptionSeqCookie": false,
    "maintenanceFlag": false,
    "bufferETACookie": false,
    "multiShippingDiscountFlag": false,
    "newFitmentFlag": false,
    "surveyOptInFlag": true,
    "crossSellFlag": false,
    "skuMappingFlag": false,
    "paySplitCookie": false,
    "callDisableFlag": true,
    "zipPaymentFlag": "c",
    "hassleFreeReturn": true,
    "lifetimeReplacement": true,
    "cpn_off": false
}
2011 Jeep Wrangler

2011 Jeep Wrangler Accessory Belt Idler Pulleys

Refine by:

Shop Catalog

Showing 1 - 15 of 33 results
Display item:
15
30
45
Sort by:
Accessory Belt Idler Pulley, 17mm or 0.66 in. I.D, 2.76 in. OD, 0.96 in. Pulley Width, Serpentine, Flat
Part Number: REPB317404
Guaranteed to Fit
$10.27
Vehicle Fitment
  • 2011 Jeep Wrangler Unlimited Sahara 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited Sport 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited Rubicon 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited 70th Anniversary 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Sahara 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Rubicon 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler 70th Anniversary 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Sport 6 Cyl 3.8L With A.C.
Product Details
Notes : 17mm or 0.66 inches I.D; Sepentine; Flat; 2.76 in. OD; 0.96 in. WWarranty : 1-year Replacement unlimited-mileage warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Numberof Grooveson Pulley : 0Interchange Part Number : 89133, 36323, 231133, 419598, 88974506, 2528725100, 11281427252, 98010237100, 04792835AA, 1341A005, 1753078K01, 31180RB0J01Replaces OE Number : 36323, 231133, 419598, 88974506, 2528725100, 11281427252, 98010237100, 04792835AA, 1341A005, 1753078K01, 31180RB0J01Recommended Use : OE ReplacementProduct Fit : Direct FitReturns Policy : 30-Day Return Policy
Accessory Belt Idler Pulleys, 6 Cylinder, 3.8L Engine, For Models with Air Conditioning
Part Number: SET-REPB317404-2
Guaranteed to Fit
$18.99
Vehicle Fitment
  • 2011 Jeep Wrangler Unlimited Sahara 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited Sport 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited Rubicon 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited 70th Anniversary 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Sahara 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Rubicon 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler 70th Anniversary 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Sport 6 Cyl 3.8L With A.C.
Product Details
Notes : 2.76 in. OD; 0.96 in. W; FlatComponents : (2) Accessory Belt Idler PulleysWarranty : 1-year Replacement unlimited-mileage warrantyQuantity Sold : Set of 2Prop 65 Warning :

Warning SymbolWARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Numberof Grooveson Pulley : 0Interchange Part Number : 89133, 36323, 231133, 419598, 88974506, 2528725100, 11281427252, 98010237100, 04792835AA, 1341A005, 1753078K01, 31180RB0J01Replaces OE Number : 36323, 231133, 419598, 88974506, 2528725100, 11281427252, 98010237100, 04792835AA, 1341A005, 1753078K01, 31180RB0J01Recommended Use : OE ReplacementProduct Fit : Direct FitReturns Policy : 30-Day Return Policy
Accessory Belt Idler Pulley - Direct Fit, Sold individually
Part Number: REPF317405
Guaranteed to Fit
$9.49
Vehicle Fitment
  • 2011 Jeep Wrangler Unlimited Sahara 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler Sahara 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler 70th Anniversary 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler Unlimited Sport 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler Rubicon 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler Unlimited Rubicon 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler Sport 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler Unlimited 70th Anniversary 6 Cyl 3.8L GAS, Without A.C.
Product Details
Notes : Plastic; Serpentine; 6-grooved; 0.67 in. inside diameter; 3.54 in. outside diameter; 1.62 in. widthWarranty : 1-year Replacement unlimited-mileage warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Numberof Grooveson Pulley : 6Interchange Part Number : 36157, 36157, 45069, 49123, 89174, 231130, 419675, 900598, 53034002AA, 6L3Z6C348A, 900598A, GT36157Replaces OE Number : 36157, 45069, 49123, 89174, 231130, 419675, 900598, 53034002AA, 6L3Z6C348A, 900598A, GT36157Recommended Use : OE ReplacementProduct Fit : Direct FitReturns Policy : 30-Day Return Policy
Accessory Belt Idler Pulley, 2.75 in. OD, 1 in. Pulley Width, Flat, Serpentine Type, Back Idler
Part Number: REPI317401
Guaranteed to Fit
$6.01
Vehicle Fitment
  • 2011 Jeep Wrangler Unlimited Sahara 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited Sport 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited Rubicon 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited 70th Anniversary 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Sahara 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Rubicon 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler 70th Anniversary 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Sport 6 Cyl 3.8L With A.C.
Product Details
Notes : 2.75 in. OD; 1 in. W; Flat; Serpentine type; Back idlerWarranty : 1-year Replacement unlimited-mileage warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Interchange Part Number : 89133Recommended Use : OE ReplacementProduct Fit : Direct FitReturns Policy : 30-Day Return Policy
Accessory Belt Idler Pulleys, 6 Cylinder, 3.8L Engine, For Models with Air Conditioning
Part Number: SET-REPI317401-2
Guaranteed to Fit
$11.49
Vehicle Fitment
  • 2011 Jeep Wrangler Unlimited Sahara 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited Sport 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited Rubicon 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited 70th Anniversary 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Sahara 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Rubicon 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler 70th Anniversary 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Sport 6 Cyl 3.8L With A.C.
Product Details
Components : (2) Accessory Belt Idler PulleyWarranty : 1-year Replacement unlimited-mileage warrantyQuantity Sold : Set of 2Prop 65 Warning :

Warning SymbolWARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Interchange Part Number : 89133Recommended Use : OE ReplacementProduct Fit : Direct FitReturns Policy : 30-Day Return Policy
Accessory Belt Idler Pulley, Serpentine, Flat
Part Number: REPM317402
Guaranteed to Fit
$7.49
Vehicle Fitment
  • 2011 Jeep Wrangler Unlimited Sahara 6 Cyl 3.8L With Air Conditioning
  • 2011 Jeep Wrangler Unlimited Sport 6 Cyl 3.8L With Air Conditioning
  • 2011 Jeep Wrangler Unlimited Rubicon 6 Cyl 3.8L With Air Conditioning
  • 2011 Jeep Wrangler Sahara 6 Cyl 3.8L With Air Conditioning
  • 2011 Jeep Wrangler Rubicon 6 Cyl 3.8L With Air Conditioning
  • 2011 Jeep Wrangler Sport 6 Cyl 3.8L With Air Conditioning
Product Details
Notes : Serpentine; FlatWarranty : 1-year Replacement unlimited-mileage warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Interchange Part Number : 38018, 89144, 0002020019, 6112000270Replaces OE Number : 6112000270Recommended Use : OE ReplacementProduct Fit : Direct FitReturns Policy : 30-Day Return Policy
No Slack Series Accessory Belt Idler Pulley - Direct Fit, Sold individually
Part Number: DY89144
Guaranteed to Fit
$18.99
Vehicle Fitment
  • 2011 Jeep Wrangler All Submodels All Engines
Product Details
Warranty : Dayco limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Series : No Slack SeriesInterchange Part Number : REPM317402, 89070, 0002020019Product Fit : Direct Fit
Accessory Belt Idler Pulley - Direct Fit, Sold individually
Part Number: GAT36157
Guaranteed to Fit
$24.49
Vehicle Fitment
  • 2011 Jeep Wrangler Unlimited Sahara 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler Sahara 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler 70th Anniversary 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler Unlimited Sport 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler Rubicon 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler Unlimited Rubicon 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler Sport 6 Cyl 3.8L GAS, Without A.C.
  • 2011 Jeep Wrangler Unlimited 70th Anniversary 6 Cyl 3.8L GAS, Without A.C.
Product Details
Warranty : Lifetime Gates limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Numberof Grooveson Pulley : 6Interchange Part Number : REPF317405, 36157, 45069, 49123, 89174, 231130, 419675, 900598, 53034002AA, 6L3Z6C348A, 900598A, GT36157Replaces OE Number : 36157, 45069, 49123, 89174, 231130, 419675, 900598, 53034002AA, 6L3Z6C348A, 900598A, GT36157Product Fit : Direct Fit
OE Solutions Series Accessory Belt Idler Pulley - Direct Fit, Sold individually
Part Number: RB419725
Guaranteed to Fit
$30.99
Vehicle Fitment
  • 2011 Jeep Wrangler Unlimited Sahara 6 Cyl 3.8L
  • 2011 Jeep Wrangler Sahara 6 Cyl 3.8L
  • 2011 Jeep Wrangler 70th Anniversary 6 Cyl 3.8L
  • 2011 Jeep Wrangler Unlimited Sport 6 Cyl 3.8L
  • 2011 Jeep Wrangler Rubicon 6 Cyl 3.8L
  • 2011 Jeep Wrangler Unlimited Rubicon 6 Cyl 3.8L
  • 2011 Jeep Wrangler Sport 6 Cyl 3.8L
  • 2011 Jeep Wrangler Unlimited 70th Anniversary 6 Cyl 3.8L
Product Details
Notes : 2.3 mm Material Thickness; 24 mm Maximum Belt Width; 70 mm Outside Diameter; 17 mm Pulley Bearing Inside Diameter; 12 mm Pulley Bearing Width; 37.6 mm Pulley Diameter; 24.5 mm Pulley Width; Black Color; Standard Grade Type; Serpentine Pulley TypeWarranty : Lifetime Dorman limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Series : OE Solutions SeriesInterchange Part Number : 38018, 89133, 89144, 4891720AA, 06F903315P, SK89133, 36323, 49024Replaces OE Number : 38018, 89133, 89144, 4891720AA, 06F903315P, SK89133, 36323, 49024Material : PlasticRecommended Use : OE ReplacementProduct Fit : Direct Fit
Accessory Belt Idler Pulley - Direct Fit, Sold individually
Part Number: 4891720AA
Guaranteed to Fit
$18.49
Vehicle Fitment
  • 2011 Jeep Wrangler Unlimited Sahara 6 Cyl 3.8L Smooth
  • 2011 Jeep Wrangler Sahara 6 Cyl 3.8L Smooth
  • 2011 Jeep Wrangler 70th Anniversary 6 Cyl 3.8L Smooth
  • 2011 Jeep Wrangler Unlimited Sport 6 Cyl 3.8L Smooth
  • 2011 Jeep Wrangler Rubicon 6 Cyl 3.8L Smooth
  • 2011 Jeep Wrangler Unlimited Rubicon 6 Cyl 3.8L Smooth
  • 2011 Jeep Wrangler Sport 6 Cyl 3.8L Smooth
  • 2011 Jeep Wrangler Unlimited 70th Anniversary 6 Cyl 3.8L Smooth
Product Details
Notes : SmoothWarranty : 1 year or 12,000-mile Crown limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Interchange Part Number : REPB317404Replaces OE Number : 4891720, 68061368AARecommended Use : OE ReplacementProduct Fit : Direct Fit
Accessory Belt Idler Pulley - Direct Fit, Sold individually
Part Number: 53034002AA
Guaranteed to Fit
$18.49
Vehicle Fitment
  • 2011 Jeep Wrangler Rubicon 6 Cyl 3.8L 6 Grooves, Without Air Conditioning
  • 2011 Jeep Wrangler Sahara 6 Cyl 3.8L 6 Grooves, Without Air Conditioning
  • 2011 Jeep Wrangler 70th Anniversary 6 Cyl 3.8L 6 Grooves, Without Air Conditioning
  • 2011 Jeep Wrangler Unlimited Rubicon 6 Cyl 3.8L 6 Grooves, Without Air Conditioning
  • 2011 Jeep Wrangler Unlimited Sport 6 Cyl 3.8L 6 Grooves, Without Air Conditioning
  • 2011 Jeep Wrangler Sport 6 Cyl 3.8L 6 Grooves, Without Air Conditioning
  • 2011 Jeep Wrangler Unlimited Sahara 6 Cyl 3.8L 6 Grooves, Without Air Conditioning
  • 2011 Jeep Wrangler Unlimited 70th Anniversary 6 Cyl 3.8L 6 Grooves, Without Air Conditioning
Product Details
Notes : Without A/CWarranty : 1 year or 12,000-mile Crown limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Replaces OE Number : 53034002Recommended Use : OE ReplacementProduct Fit : Direct Fit
No Slack Series Accessory Belt Idler Pulley - Direct Fit, Sold individually
Part Number: DY89174
Guaranteed to Fit
$43.49
Vehicle Fitment
  • 2011 Jeep Wrangler All Submodels All Engines without A.C.
Product Details
Notes : 1 bearing; 17 mm ID; 90 mm pulley diameter; 30 mm pulley W; 06 rib max belt W; Steel material; Serpentine type; Non-flangeWarranty : 1 year or 12,000-mile Dayco limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Series : No Slack SeriesNumberof Grooveson Pulley : 6Interchange Part Number : REPF317405Recommended Use : OE ReplacementProduct Fit : Direct Fit
OE Replacement Series Accessory Belt Idler Pulley - Direct Fit, Sold individually
Part Number: MOP04891720AA
Guaranteed to Fit
$53.99
Vehicle Fitment
  • 2011 Jeep Wrangler Unlimited Sahara 6 Cyl 3.8L
  • 2011 Jeep Wrangler Sahara 6 Cyl 3.8L
  • 2011 Jeep Wrangler 70th Anniversary 6 Cyl 3.8L
  • 2011 Jeep Wrangler Unlimited Sport 6 Cyl 3.8L
  • 2011 Jeep Wrangler Rubicon 6 Cyl 3.8L
  • 2011 Jeep Wrangler Unlimited Rubicon 6 Cyl 3.8L
  • 2011 Jeep Wrangler Sport 6 Cyl 3.8L
  • 2011 Jeep Wrangler Unlimited 70th Anniversary 6 Cyl 3.8L
Product Details
Location : Above CrankshaftWarranty : 36-month or 36,000-mile Mopar limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Condition : NewSeries : OE Replacement SeriesRecommended Use : OE ReplacementProduct Fit : Direct Fit
Accessory Belt Idler Pulley - Direct Fit, Sold individually
Part Number: MOP53034002AA
Guaranteed to Fit
$75.99
Vehicle Fitment
  • 2011 Jeep Wrangler Unlimited Sport 6 Cyl 3.8L
  • 2011 Jeep Wrangler Sport 6 Cyl 3.8L
  • 2011 Jeep Wrangler Rubicon 6 Cyl 3.8L
  • 2011 Jeep Wrangler Sahara 6 Cyl 3.8L
  • 2011 Jeep Wrangler Unlimited Sahara 6 Cyl 3.8L
  • 2011 Jeep Wrangler 70th Anniversary 6 Cyl 3.8L
  • 2011 Jeep Wrangler Unlimited Rubicon 6 Cyl 3.8L
  • 2011 Jeep Wrangler Unlimited 70th Anniversary 6 Cyl 3.8L
Product Details
Warranty : 36-month or 36,000-mile Mopar limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Condition : NewRecommended Use : OE ReplacementProduct Fit : Direct Fit
No Slack Series Accessory Belt Idler Pulley - Direct Fit, Sold individually
Part Number: DY89133
Guaranteed to Fit
$32.49
Vehicle Fitment
  • 2011 Jeep Wrangler Unlimited Sahara 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited Sport 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited Rubicon 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Unlimited 70th Anniversary 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Sahara 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Rubicon 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler 70th Anniversary 6 Cyl 3.8L With A.C.
  • 2011 Jeep Wrangler Sport 6 Cyl 3.8L With A.C.
Product Details
Notes : Serpentine Assembly Pulley Type; 06 Rib Max Belt Width; 70 mm Pulley Diameter; 24.5 mm Pulley Width; 17 mm Bearing ID; (1) Bearing; FlatWarranty : 1 year or 12,000-mile Dayco limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Condition : NewSeries : No Slack SeriesInterchange Part Number : REPI317401, 36323, 231133, 419598, 88974506, 2528725100, 11281427252, 98010237100, 04792835AA, 1341A005, 1753078K01, 31180RB0J01Replaces OE Number : 36323, 231133, 419598, 88974506, 2528725100, 11281427252, 98010237100, 04792835AA, 1341A005, 1753078K01, 31180RB0J01Material : PolymerRecommended Use : OE ReplacementProduct Fit : Direct Fit
Page 1 of 3 | Showing 1 - 15 of 33 results

Top Rated Products

Very easy to replace and quick ship on this part.
Andrew B.
VERIFIED PURCHASER
Fixed my issue..so much quieter!
Matt R.
VERIFIED PURCHASER
great part smooth and quiet
Stewart O.
VERIFIED PURCHASER

Popular Products

Helpful Automotive Resources

Where is the Idler Pulley Located?
Where is the Idler Pulley Located?Accessing the idler pulley can be deceptively tricky and you’ll need tools like a socket set and a torque wrench. It varies though, and on some engines it’s very easy but the belt needs to be removed first. .u3bac4795d176ea268a646d1c916030f2 { padding:0px; margin: 0; padding-top:1em!important; padding-bottom:1em!important; width:100%; display: block; font-weight:bold; background-color:#eaeaea;
Bad Idler Pulley Symptoms Plus Replacement Recommendations
Bad Idler Pulley Symptoms Plus Replacement RecommendationsTo fully understand the function of an idler pulley, let’s look at how the whole mechanism works. If you own a modern vehicle, it probably has one serpentine belt rather than multiple V-belts.