Symptoms of a Bad or Failing Idler Pulley

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Cost of Replacing a Bad or Failing Idler Pulley

Common signs include a damaged bearing or pulley, squealing from the engine area, and visibly worn pulleys. Our certified technicians can come to you and diagnose the problem. You will receive a $30 credit towards any follow-up repairs that result from the diagnostic. Following are example prices for Idler Pulley Replacement. Click on the button below to get an upfront quote for your car.

Cars Estimate Parts Cost Labor Cost Savings Average Dealer Price
2004 Chevrolet Impala $113 $21.85 $91.00 30% $161.60
2007 GMC Yukon $124 $33.16 $91.00 28% $172.91
2008 Ford Expedition $92 $21.85 $70.00 28% $129.35
2008 BMW X5 $148 $78.35 $70.00 20% $185.85
2004 BMW 330Ci $121 $51.11 $70.00 23% $158.61
2003 Jaguar S-Type $102 $32.48 $70.00 26% $139.98
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How to Diagnose a Bad or Failing Idler Pulley?

idler pulley

Idler pulleys are engine pulleys that are responsible for guiding and tensioning the engine drive belts. The engine drive belts are routed in a specific manner around the various engine accessories, such as the alternator, water pump, power steering pump, and AC compressor. The idler pulley is meant to provide another smoothly rotating point for the engine belt to loop around, so that the desired routing can be achieved. Most engines use one idler pulley, and one tensioner pulley, though some designs do use more than one idler. Over time, idler pulleys will eventually wear out and need to be replaced. Usually a bad or failing idler pulley will produce a few symptoms that can notify the driver of an issue.

1. Visibly worn pulleys

One of the first symptoms of an issue with an idler pulley is visible wear on the pulley. Over time, as the pulley spins against the belt, both components will eventually start to wear. This may lead to visible scoring marks on the surface of the pulley, as a result of contact with the belt. Eventually the pulley and belt will wear to the point of reducing tension, which may lead to the belt slipping.

2. Belt squealing

Another common symptom of a possible issue with the idler pulley is squealing from the engine belts. If the surface of the idler pulley wears, or the pulley seizes or binds it may cause the engine belt to squeal as a result of it rubbing against the surface of the pulley. In some instances a bad pulley may bind or slip and cause the belt to squeal when the engine is first started. The issue will eventually worsen as the pulley continues to wear.

3. Damaged bearing or pulley

Another symptom, more visible, symptom of an issue with the idler pulley is a damaged bearing or pulley. In more serious cases, the bearing, or pulley itself may wear out to the point of breaking or cracking, and coming apart, or seizing. This can upset the rotation of the belt and lead to all sorts of problems. A broken or seized pulley can quickly lead to a torn belt, or in less serious cases, the belt falling off of the engine. An engine without a belt can quickly run into issues such as overheating and stalling, as it’s the drive belt that allows the engine accessories to function.

Idler pulleys are a common component found on the majority of road going vehicles that will eventually require replacement, especially in high mileage vehicles. Any of the engine pulleys are very important to the overall operation of the engine, as it’s the serpentine belt and pulleys that allow the engine to properly function after it has been started. If you suspect that your idler pulley may be having an issue, have the vehicle inspected by a professional technician, such as one from YourMechanic, to determine if the pulley should be replaced.

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YourMechanic Idler Pulley Replacement Service

Average Rating

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Number of Reviews

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Rating Summary
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Kenneth

17 years of experience
335 reviews
Kenneth
17 years of experience
Excellent service!! Best knowledgeable, honest, professional mechanic in LA. Kenneth went far and beyond to help solve problem with my BMW.
2002 BMW 540I - IDLER PULLEY - LOS ANGELES, CALIFORNIA

Matthew

30 years of experience
268 reviews
Matthew
30 years of experience
Arrived on time, selected his tools and never stopped till he was finished with the job. Even allowed me to hang-out with him SOME while he worked.
2004 TOYOTA COROLLA - IDLER PULLEY - NORFOLK, VIRGINIA

Jesus

11 years of experience
9 reviews
Jesus
11 years of experience
My car had a busted fan belt, so I thought. So I made an appointment to have it replaced by a mechanic from YourMechanic.com. Jesus Ramirez was my mechanic. He was on time, professional and answered all my questions. He diagnosed the problem was the bad idler pulley and so ordered additional parts. he got the problem fixed and car going again. He pointed out the leak from the power steering reservoir probably caused the pulley to go bad.
2000 BMW 323I - IDLER PULLEY - CHINO, CALIFORNIA

Tyrone

8 years of experience
365 reviews
Tyrone
8 years of experience
Great service as always. Tyrone is my go-to mechanic. Always honest & upfront about when I can hold off on something & when I need it now.
2009 NISSAN MURANO - IDLER PULLEY - FALLS CHURCH, VIRGINIA

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