The Owner’s Manual Says that It is Time
Most modern cars that roll off the dealer’s lot as a new vehicle will have a 60,000 to 100,000-mile life expectancy for the serpentine belt, tensioners, and idler pulleys. If your owner’s manual lists replacing the serpentine belt as part of your 75,000-mile maintenance, it is wise to take them up on the suggestion. These belts will wear out sooner or later.
The Engine Light is On
If a pulley or tensioner goes out of alignment and causes the serpentine belt to slip, the hiccup in power transfer to vital systems in your vehicle will trigger the check engine light to come on. While that light does not always indicate a need for immediate service, it is smart to have a diagnostic run to make sure that catastrophic failure is not imminent.
Visible Wear or Fluids on the Serpentine Belt
When you are conducting a visual inspection under the hood while adding washer fluid and notice that your serpentine belt is crooked, cracking, or is shiny due to leaking oil, you should pop in a replacement serpentine belt as soon as possible. A belt that has popped out of alignment will wear unevenly, causing unpredictable failure at the worst possible time. Oil and lubricants will degrade the material of the belt resulting in premature failure. If you see damage, treat it like the belt has failed completely.
Squealing Under the Hood
The belt is not always the first part of the system to fail. A tensioner that is bent or cracked will cause the belt to slip out of alignment. You may notice squealing coming from under the front of the car while idling, under acceleration, or even after the ignition engages. That is a warning bell that you need to conduct an immediate inspection and possible repair of a pulley, tensioner, or the entire system.
Sudden Loss of Power Steering or High Engine Temperature
It is called a serpentine belt because it winds its way around a number of different gears that connect to a variety of pumps and fans. When the belt gives out, your power steering will feel like it is seized up, the circulating pump for your radiator stops working, and even the fans that circulate your air conditioning may stop. The belt failure can damage all these other systems, raising your repair bill exponentially.
Modern cars generally use a tensioner to keep your serpentine in place and eases the replacement procedure for most models. Replacing a bent tensioner or broken pulley at the same time as the belt is always recommended to extend the life of your car.