Auto Service World
Feature   May 1, 2014   by Steve Pawlett

Cooling System Care: Keeping Cool Under the Hood

Today’s higher-performance engines produce more power and thus more heat, so a properly functioning cooling system is essential to maintain the engine at the proper operating temperature. Despite this, one of the most overlooked maintenance items on vehicles is the cooling system and its accessory drive components.
As little as a 5% loss of rib material in a serpentine belt can cause loss of tension or belt slippage, which can affect the overall performance of components and lead to their failure. It’s not just about the belt; it’s about the system.
The serpentine belt drive usually consists of a single belt that powers a variety of accessory drives. Roughly 15% of all vehicles on the road today have a worn belt that needs to be replaced, and about 90% of all belt failures happen on vehicles that are over eight years old. But there is a misconception within the industry about checking for worn belts on today’s vehicles. Some professional technicians still look for cracks in the belt when analyzing the condition of the serpentine belt. That was a great way to check belts in the past, but today’s belts have changed and it has become more difficult for technicians to identify worn belts.
Today’s belts start out with a V profile, and as they wear, the V turns into a U. Once the belt is worn, it will have less surface area contact with the pulley and begin to fail or make noise. Leading serpentine belt manufacturers provide gauges to help measure belt wear, similar to a tire tread depth gauge. The free gauges are placed into the rib, and if the user can’t feel the plastic, the gauge leg has dropped too deep into the rib, meaning the V has worn into a U and the belt is worn out. The technician can also use the crown of the gauge to inspect belts for wear. If the user can move the gauge side to side or see light through the ribs, that is a sign that the belt is worn.
Jobbers may be surprised to learn that many warranty claim failures on alternators and other parts are actually caused by worn or improperly tensioned belts. As more material is lost, the pulleys ride deeper into the belt valleys, resulting in slip, noise, and even hydroplaning. A slipping belt (shiny or glazed-looking belt) can be caused by a worn tensioner, or worn or contaminated pulleys. Additionally, it’s important to inspect the pulleys for proper alignment, because as little as one degree of misalignment can cause belt chirp. Installing a new belt will only temporarily fix the problem, and within as little as 5,000 km, the belt will begin to chirp again if not corrected.
The most important element of the drive system is the automatic tensioner. It’s important to point out to your customer that a premium tensioner will provide superior casting, dampen peak loads during engine acceleration and deceleration, and truly help extend the life of other system components that would otherwise be susceptible to engine failure from engine vibrations. In fact, automatic belt tensioners are designed with the same life cycle as the belt and should be replaced together.
Gates makes belt, pulley, and tensioner replacement easy with the recent introduction of its Accessory Component Kit. Gates has also designed a free online training portal for technicians and counter staff, featuring an Accessory Belt Drive System training course that will help jobbers and technicians solve common problems of the belt drive system, improve system performance, and reduce customer comebacks.
CRP Automotive also offers a range of ContiTech Pro Series Plus Timing Kits that solve special service problems by providing technicians with all of the components needed to perform a proper timing belt and water pump service. CRP includes additional components to help technicians handle specific application issues that are typically encountered during the service. CRP now produces over 150 kits for more than 2,000 applications.
Vehicles are getting older and average mileage is getting higher. The average age of vehicles on the road today is 11.3 years, a 14% increase from 2007. The Automotive Aftermarket Industry Association conducts its Car Care Check Lane study every year during National Car Care Month to identify services and worn parts on random vehicles. For the past 10 years, this study has shown that one out of every five vehicles on the road has a worn belt that needs to be replaced, which is one of many reasons why jobbers should recommend to customers to have their vehicle cooling system inspected.
Noisy belts have not gone away. In fact, it is one of the biggest issues today.
Here’s why:
Types of Belt Noise
Squeal – Result of a relative slip between the belt and a pulley. Caused by:
• Low belt tension
• High loads resulting in bearing drag or accessory on the verge of failure
• High accessory load with insufficient belt wrap on the pulley
Chirp – Result of relative misalignment, the No. 1 cause of belt noise, between consecutive pulleys in a drive. Caused by:
• Accessory bracket and shaft deflection
• Belt installed one rib out of groove on one or more pulleys
Today’s EPDM belts are stiffer and belts are being replaced on vehicles with nearly 160,000 kilometres, and the belt drives in those vehicles are far from perfect. The vehicles have worn pulleys and slight misalignments that the new belt needs to contend with. In the past, old-style neoprene belts were softer and more forgiving to these imperfections. The new, stiffer EPDM belts tend to make noise with these misalignments. Belt drives have also become much more complicated, touching over 10 points of contact and leaving more opportunities for misalignments.
Noise can also be caused by misalignment or tension. Dayco offers a simple trick of the trade to help figure this out. Take a water bottle and spray the rib side of the belt while the vehicle is running. If the noise goes away, it’s a misalignment. Another way is to rev the engine and if the noise goes away, it’s misalignment. When you spray the ribs and the noise gets louder, the issue is tension. Again, if you rev the engine and the noise gets louder, it’s tension.
When replacing a serpentine belt on vehicles with fixed locked drives, check for:
• Over-Tensioning – This puts undue stress on the bearings within the drive system’s various components and could cause premature bearing failure. In addition, over-tensioning could cause the belt to separate as the pulleys cut into the belt.
• Under-Tensioning – Belt slippage will occur when the belt is placed under a load situation – the consequence of which is that the belt becomes glazed or slick. This results in belt squeal, premature cracking, or early belt failure.
• Worn drive system components and pulley misalignment – Edge cord failure/groove jumping can be caused by worn drive system pulleys or tensioner components. Always inspect and replace these components as necessary.
When replacing a serpentine belt on vehicles with automatic belt tensioners, check for:
• Misalignment, wear, and bearing failure of drive system components – Uneven belt wear or premature belt failure will occur if these items are not inspected and repaired or replaced.
• Improper belt seating – Extreme care should be taken when reinstalling the serpentine belt to insure that the belt is properly seated and aligned in all pulley grooves. If not properly seated, the belt can “ride out” of the grooves, resulting in damage to the belt.
To help fix a customer’s noisy accessory drive problems, Dayco now provides a Laser Alignment Tool, which can be found in the Dayco Belt Diagnostic Kit.
The machined aluminum body is lightweight and durable, and has magnets that secure it into the grooves of the reference pulley, which is usually the crankshaft pulley, ensur
ing a stable stage for accurate laser projection.
Veyance, marketer of Goodyear brand belts and hoses, offers the DataDrive Market Intelligence tool. It uses information about geographical locations, vehicle types, and other factors to help distributors of Goodyear Engineered Products stock the right products specifically for their local markets, with up-to-date information down to the part number, and helps identify potential buyers in the area.
Gates has designed an online training portal for technicians and counter-personnel. This free online portal features an Accessory Belt Drive System (ABDS) training course that will help counter staff and technicians solve common problems of the belt drive system, improve system performance and reduce customer comebacks.
Whether you are dealing with a customer walking in with a broken belt in his hand or a professional technician on the phone, by utilizing all the tools made available to you by your suppliers, you can ensure your customers will leave satisfied that they received the best advice and the best quality components for their vehicle.