FAQs

If we can’t see it or hear it, how do we identify EPDM belt wear?

Think of EPDM belt wear the way you think of tire wear. After many miles of running on the road, a tire’s tread gradually wears down. Over time, belts experience a similar loss in material or rib wear. When this happens, a belt loses its ability to grip or function properly – it can slip – which puts a strain on other components within your engine, causing them to malfunction and potentially fail. Although not always the case with EPDM belts, noise is often your first and most obvious clue that your belt and other system components should be replaced.

When it comes to inspection and repair, think I-60/R-90

As a best practice, we always advise technicians and vehicle owners to Be System Smart by knowing the Car Care Council’s recommended service interval schedule. Start inspecting the serpentine system at 60K miles, and replace worn components by 90K miles or as advised by the manufacturer. An easy way to remember this recommended interval is I-60/R-90.

EPDM Belt Durability

EPDM belts are more durable than traditional chloroprene belts due to their resistance to cracking, lasting over 100,000 miles without visible cracks.

Diagnosing EPDM Belt Wear

Instead of relying on visual cracks, focus on material loss on the belt ribs as a better indicator of wear, caused by exposure to contaminants and misalignments.

Effect of Material Loss

Reduced rib material leads to decreased clearance between the belt ribs and pulley sheaves, causing potential belt slip due to increased contact and resulting in a form of hydroplaning.

Diagnostic Approach

Technicians should assess the entire accessory drive system for signs of belt wear, considering the performance of the belt, tensioner, pulleys, and other system components like alternator, power steering, and A/C, especially during replacements or at 60,000-mile checks. Regular inspections using tools like the Gates belt wear gauge can prevent more significant failures, and components should be replaced at recommended intervals to avoid costly issues.

Belt Material Loss Impact

Even a minor 5% loss in rib material due to wear significantly affects belt performance, while a 10% belt slippage noticeably impacts vehicle drivability, especially affecting critical functions like the alternator during extreme weather conditions.

System Dynamics with Component Change

Pairing a new alternator with old belt and tensioner significantly increases system vibration. This vibration, though not always felt or heard by drivers, can cause belt noise, hasten bearing wear in drive components, and lead to premature system failure.

Tensioner Arm Cycles and Consequences

An average automatic belt tensioner arm cycles over a billion times per 100,000 vehicle miles. If only one system component is changed, such as pairing a new alternator with old belt and tensioner, excessive arm vibration occurs. This vibration can lead to issues like belt noise, accelerated component wear, and even failure within the tensioner itself.

Compromised Component Performance

Failure to address these issues could stress the belt and other accessory components, compromising the performance of the new component. This situation necessitates additional costs for re-diagnosis and repair.

Primary Functions of Automatic Belt Tensioner

Applying correct tension to the serpentine belt for transferring torque from the crankshaft to system accessories.
Smoothing out crankshaft vibration associated with power transfer.

Misconception about Tensioner Lifespan

Contrary to the belief that automatic belt tensioners last the vehicle's lifetime, they contain internal components that wear out over time. Replacing the tensioner, although relatively inexpensive, is crucial to protect other components like the water pump, alternator, and A/C compressor from undue stress and premature failure.

Impact of Tensioner Wear

Tensioner wear causes uneven tension distribution, premature belt edge wear, and tensioner pulley misalignment. This can lead to belt slippage, even minimal misalignment causing reduced system component output or complete failure.

Diagnosing Tensioner Issues

Essential practice involves diagnosing the tensioner before belt replacement or any other serpentine system component change. Check for excessive vibration in the tensioner arm while the engine runs with the air conditioning on. Visible tensioner arm vibration indicates the need for replacement. Also, inspect the pulley surface and spin it to ensure proper bearing operation with no resistance when the engine is off.

Complete System Repair and Maintenance

The tensioner is a critical link in the accessory belt drive system. Replacing the tensioner may necessitate replacing other system components to ensure comprehensive system repair. Following Car Care Council recommendations, start inspecting the serpentine system at 60,000 miles and replace system components by 90,000 miles or as per manufacturer advice for optimal maintenance.

What is Proin euismod nisi sit amet nibh tristique?