Your vehicle is made of many different and complex parts which are hard to understand if you are not a mechanic. One of them is the idler pulley. The idler pulley has the job of keeping and guiding the car’s tension with the serpentine belt. The belt is held in place by the pulley when the power is transferred from the car’s engine.
The drive belt uses the power of the engine to rotate the pulleys that supply the following engine components: the water pump, which cools the engine; the air conditioning; the alternator, which recharges your battery and causes the electrical devices and the power steering pump to work properly.
Because the idler pulley powers so many of your car’s critical systems, it’s important to make sure it’s in excellent condition.
How much does an idler pulley replacement cost?
As with any car repair, the amount of money you are going to spend in order to replace the idler pulley will be influenced by the mechanic/dealer you choose, your geographical location, and the make and model of your vehicle.
During our research, we found out that the replacement cost for this part on its own is pretty much the same for all types of vehicles. The average cost of hiring a professional would be anywhere between $100 and $170, including the parts.
Expect to pay anywhere between $35 and $55 for the parts. This job would take around an hour which means that you will have to pay a shop minimum fee, which in general, would be anywhere between $75 and more than $110. However, these costs would be much higher for a luxury brand vehicle.
There are situations when the bearing and/or the serpentine tensioner/belt has to be changed as well when replacing the idler pulley. This would increase the costs by another $120 to $170.
According to the RepairPal.com website, the average cost of the parts would be anywhere between $50 and $95, while for the parts you will have to pay anywhere between $85 and $200.
CarParts.com notes that an aftermarket idler pulley typically costs anywhere between $20 and $100, with some pulleys priced higher depending on the brand and other factors.
MotorVerso states that the labor cost for idler tensioner pulley replacement should range between $45 and $150, while the parts can cost between $125 and $380.
For example, you can purchase a complete kit from AutoZone, including the idler pulley, for $85 to $140. Just for the idler pulley, you will have to pay anywhere between $25 and more than $45. On Amazon, the best sellers charge anywhere between $20 and $40 for an idler pulley.
What does an idler pulley do?
The idler pulley helps apply the perfect amount of tension to keep the serpentine belt running at the proper strength and speed for optimum vehicle functionality.
The diagnosis and repair process of the idler pulley
The first sign of an idler pulley issue is the check engine light turning on. In order to confirm that the idler pulley is broken and needs to be replaced, the first thing a mechanic will do is to lose the serpentine belt to relieve the tension and physically inspect the idler pulley.
After that, the pulley will be manually turned to see if there are any looseness, grinding-like noises, resistance, or vibration. Most probably the idler pulley is broken if any of these symptoms are noticed.
The whole pulley system will be inspected when replacing the idler pulley. In most situations, the mechanic will want to replace the belt tensioners as well for your safety. Also, the drive belt will be replaced if it is faulty or broken.
Symptoms of a faulty drive belt idler pulley
There are a number of symptoms that may indicate that your car’s idler pulley is worn, including:
- Squeaking noises coming from the engine: When the serpentine belt starts to slip, it may start to squeak. This sound indicates that there is a belt tension, low belt tension, or that the idler pulley and belt do not work together properly.
- Air conditioning or power steering malfunctions: If the idler pulley breaks or is damaged, you may notice that the air conditioning is not working properly. In addition, your car’s power steering system, alternator, or water pump may fail, which can lead to a serious safety issue.
- A car breaks down: When the idler pulley breaks completely, your vehicle will lock, which can be extremely dangerous and inconvenient.
The engine test light and other indicators from the dashboard will alert you when there is a problem with the idler pulley. Never ignore the warning signs of an idler pulley failure.
When should you replace the idler pulley?
The idler pulley will have to be replaced when it starts to make noises, normally it should not be heard at all. Idler pulleys are not guaranteed for life, so they should be replaced ideally before they wear out. Depending on the manufacturer, the idler pulley can be changed at 100,000 miles on average, so it is best to check the car’s book to find out when it needs to be changed.