How long do Subaru serpentine belts last?

Most Subaru serpentine belts are expected to last about 60,000–100,000 miles (95,000–160,000 km), typically around 5–7 years, before replacement is advised. Exact timing depends on model, engine configuration, and driving conditions. Check your owner’s manual and consult a trusted mechanic for guidance specific to your vehicle.

Typical lifespan and replacement window

The belt's expected life can vary, but these ranges reflect common service schedules across Subaru models. The belt drives multiple accessories, so wear can differ based on engine layout and component condition.

• Typical replacement window: 60,000–100,000 miles (95,000–160,000 km).


• Common service interval in many climates: around 5–7 years.


• Variations by engine and model: some configurations place different loads on the belt.


• Driving conditions and maintenance: hot climates, frequent short trips, or oil leaks can accelerate wear.

Because conditions vary, treat these figures as general guidance rather than a fixed rule. Regular inspections at service intervals help prevent unexpected belt failure.

Factors that affect belt life

Several factors determine how quickly a serpentine belt wears out. The following list highlights the main influences you should monitor.

• Engine heat and temperature extremes can degrade rubber and reduce belt life.


• Quality and age of the belt material (EPDM blends are common today) and belt routing.


• Wear or failure of tensioners and idler pulleys, which can cause uneven loading or belt slippage.


• Oil, coolant, or other fluid leaks contaminating the belt surface.


• Driving style and patterns: frequent stop-and-go traffic and short trips reduce belt life compared with steady highway driving.


• Climate and environmental conditions such as dust, heat, and humidity.

Understanding these factors helps owners anticipate maintenance needs and avoid belt-driven breakdowns.

Warning signs indicating replacement is due

Look for audible and visible cues that the belt may be nearing the end of its service life.

• Squealing or chirping noises from the engine bay, especially on startup or during acceleration.


• Visible cracks, fraying, glazing, or chunking on the belt's ribs.


• Shiny or glazed belt surfaces and missing chunks.


• Wobbling or misalignment of the belt, or frequent belt tension issues.


• Check engine light or symptoms of accessory failure (e.g., dead alternator, weak power steering) if caused by a slipped belt.

If you notice any of these signs, stop driving if needed and have the belt inspected promptly. A proactive replacement can prevent belt failure and collateral damage to pulleys or the water pump.

Maintenance and replacement guidelines

Following a prudent maintenance plan helps ensure reliability and avoids unexpected breakdowns. The guidelines below reflect common industry practice for Subaru vehicles.

• Most owners plan belt replacement around 60,000–100,000 miles (95,000–160,000 km) or 5–7 years, whichever comes first. Model-year and engine type can shift this window.


• Replace the serpentine belt in conjunction with worn or suspect tensioners and idler pulleys to reduce risk of belt failure.


• Use high-quality or OEM-recommended belts and ensure the correct belt type and length for your engine.


• Inspect the belt and drive system for oil leaks, coolant leaks, or damaged pulleys and address any contamination before installing a new belt.


• After replacement, verify proper belt tension and alignment and keep records for future service.


• Harsh climates or heavy-duty driving may necessitate more frequent inspections (e.g., at 30,000–40,000 mile intervals).

In short, staying on top of inspections and replacing worn components with quality parts maximizes belt life and minimizes the risk of breakdowns.

Summary

Subaru serpentine belts typically last 5–7 years or 60,000–100,000 miles, depending on a mix of factors including engine design, driving conditions, and maintenance. Regular inspections, timely replacement of the belt and associated tensioners/pulleys, and using quality parts are the best defense against unexpected belt failure. Always follow your owner’s manual and consult a trusted technician for model-specific guidance.

Can I spray WD-40 on my serpentine belt?

No, you should not spray WD-40 on your serpentine belt because it can damage the rubber and cause it to fail. WD-40 is a water-displacing solvent, not a proper lubricant for belts, and can make the belt slippery, leading to more noise and eventual failure. 
This video explains why you should not use WD-40 on a squeaky belt: 55sHomeowner RepairYouTube · Oct 16, 2025
Why you should avoid WD-40

• It degrades rubber: The petroleum-based chemicals in standard WD-40 can break down the rubber over time. 
• It's a temporary fix at best: If it quiets a squeak, it's only because it's making the belt slippery, not because it's fixing the problem. The squeaking will likely return or get worse as the belt's performance is degraded. 
• It attracts grime: As a solvent and light oil, it can attract dirt and grit, which can further damage the belt and pulleys. 

What to do instead

• Use a dedicated belt dressing: Auto parts stores sell products specifically formulated to condition belts and eliminate squeaks without causing damage. 
• Identify the root cause of the squeak: A squeaking belt is often a sign of a bigger issue, such as a worn-out belt, an old tensioner pulley, or a misaligned component. It is best to diagnose and fix the underlying problem. 
• Clean the belt: If you have already sprayed WD-40, you can try cleaning the belt and pulleys with a mild detergent and water to remove the residue, but the best long-term solution is to replace the belt if it is old or worn. 

What is the life expectancy of a serpentine belt?

A serpentine belt typically lasts between 50,000 and 100,000 miles, though this can vary based on factors like your driving habits, climate, and vehicle type. For vehicles driven less than 10,000 miles annually, consider replacing the belt every three to five years, as it still degrades from exposure to heat and other elements even when not in use. Regular inspection is key, and signs of a failing belt include squealing noises, cracks, and a loss of function in accessories like the power steering or air conditioning.
 
Factors affecting serpentine belt life

• Driving conditions: Extreme temperatures, road conditions, and frequent stop-and-go traffic can shorten a belt's lifespan. 
• Vehicle type: Different makes and models have different recommendations, so checking your owner's manual is a good idea. 
• Maintenance: Exposure to oil contamination can also lead to premature wear. 
• Age: Even if the car isn't driven much, a belt can degrade over time due to exposure to heat, friction, and the atmosphere. 

When to replace the belt

• Mileage: Follow the manufacturer's recommended interval, which is generally between 50,000 and 100,000 miles. 
• Age: If you drive infrequently, consider a replacement every three to five years or every four to six years if you drive under 10,000 miles annually. 
• Visual inspection: Look for cracks, fraying, missing chunks, or glossy/shiny areas. The belt should not show signs of wear, and you should not see any cords showing. 
• Audible cues: A squealing, screeching, or chirping noise from the engine is often a sign that the belt is slipping. 
• System failure: If your power steering is sluggish, the air conditioning stops working, or the battery is not charging properly, the serpentine belt is a likely culprit. 

How to tell if a serpentine belt needs replacing?

You can tell a serpentine belt needs replacing by listening for squealing or chirping noises, looking for visible damage like cracks or fraying, or noticing that power steering, air conditioning, or the battery warning light are not working correctly. Other signs include engine overheating or the smell of burnt rubber. 
Audible signs

• Squealing or chirping: A loud squeal, especially when accelerating, is a common symptom of a worn or slipping belt. 
• Burnt rubber smell: This can indicate the belt is overheating and slipping. 

Visual signs

• Cracks, fraying, or splitting: Inspect the belt for any cracks, especially on the ribbed side, or if it looks frayed or is starting to split. 
• Missing chunks or ribs: If pieces of the belt are missing or the ribs are damaged, it's time for a replacement. 
• Glazing: The smooth, shiny surface on the backside of the belt can be a sign of wear. 

This video demonstrates how to check for cracks and fraying on a serpentine belt: 59sHomeowner RepairYouTube · Dec 16, 2018
Performance issues

• Loss of power steering: If steering becomes stiff or difficult, a failing serpentine belt is a likely cause. 
• Air conditioning problems: The A/C may blow warm air or stop working altogether. 
• Engine overheating: The belt drives the water pump, so its failure can cause the engine to overheat. 
• Electrical issues: A failing belt can lead to the battery light coming on or dimming headlights, as it also drives the alternator. 
• Difficulty starting: In some cases, a completely failed belt can cause the car to have trouble starting. 

How long does a Subaru serpentine belt last?

When Should I Replace My Subaru Serpentine Belt? Most serpentine belts last for 50,000 miles or more. Consult your Subaru owner's manual for details on your specific vehicle.