Dayco Q&A

Dayco labs question and answers.

Find below a comprehensive Q&A about all things Dayco


I have been advised more than once by different people that Dayco belts are more trouble-prone and that Gates or Contitech should be utilized. Can you comment on the failure rates (massive as well as miles/time to a stretch and/or squeal point) and quality assurance of Dayco versus Gates or Continental?

 

Dayco’s lab tests have shown that Dayco belts are as durable and noise resistant as the competitor’s belt products. Since almost all belt suppliers use belt constructions utilizing EPDM rubber compounds, the flex life and overall durability of belts are very similar. The failure mode that is most prevalent in belt systems is noise, and the cause of the belt’s noise is almost always a system cause (pulley misalignment, low tension, rough/worn bearings,) as opposed to the belt. Dayco has been in business for 105 years and is selling millions of belts every year into the automotive aftermarket and to almost every major Auto and Truck Manufacturer in the world. 105 years of experience has taught us that quality and innovation are the keys to our success and survival.
Ed Rammel, Vice President Marketing


What is the time-life (as opposed to mileage) that a Dayco belt can perform before replacement is recommended? (Important for seldom-used cars)

 

Dayco’s new EPDM belts are not affected by ozone degradation as compared to the older style neoprene belts, thus time for performance will be extended (to at least 7-10 years as compared to the typical 6 years for a neoprene belt). But, storage conditions can still decrease the time recommended, such as high temperatures, high humidity, and/or oil contamination.
Jay Swope, Principle Engineer of Belt Development


What is the mileage-life that you design belts to/recommend replacement in general?

 

OE designed belts will typically run 70,000 to 100,000 miles, but it is recommended that all belts be inspected at about 50,000 miles and at every oil change after that, to ensure belt rib wear is still acceptable, as well as no failures related to edge cord fray/pop-out and/or rib cracking/chunk-out. The following link is video instructions for measuring belt wear. http://www.youtube.com/watch?v=uFlwqWZvR8Y&feature=player_embedded
Jay Swope, Principle Engineer of Belt Development

 


For rubber products such as hoses, what dressings (if any) are recommended for either looks or protective qualities from oxidation, UV, etc?

 

It is impossible to predict what ingredients may be used as protectant, cleaner, etc. There haven’t been any reports or returns to us of products that have been affected by such cleaning or treatment. Basically, any material that is chemically incompatible with the type of rubber used is going to have some effect on the hose. Most heater and coolant hoses in the light duty automotive markets use EPDM for both the tube and the cover. Any petroleum based solvent or “dressing” will cause some swelling and degradation of the EPDM. Depending on many factors, it may never be an issue. Most petroleum containing hoses (such as fuel lines) are generally made of a neoprene or CPE material that is much more resistant to petroleum based products.
Randy Foster, Director of Product Technology/Engineering


On my previous cavalier 2.2L was installed one of your poly-cog belts. The belt worked great. But I’m curious, what makes the poly-cog belt special, and better than a standard ribbed belt? I’ve heard they tend to be noisier than a normal belt (I only owned the car with that belt on it, so I can’t compare my own experience).

 

Poly-cog belts were designed to improve overall durability by increasing the flexibility of the belt as it bends around accessory pulleys. Dayco’s new Poly Rib W profile belts are not cogged, but use a new rubber formulation, EPDM, which increases the overall durability without the cogs, and improves the noise resistance of the belt by allowing the rib tips to flex whenever entering misaligned pulleys. Poly Cog belts were designed and introduced to the aftermarket in 1989 based on the serpentine drives and belt technology that existed at that time. The Poly Rib W profile belt was first introduced in 2007 and incorporated the newest rubber formulations along with the improved rib profile, designed to flex and conform in worn aftermarket drives.
Ed Rammel, Vice President Marketing

 


What is the average expected lifespan of a normal serpentine belt? Miles/years.

 

OE designed belts will typically run 70,000 to 100,000 miles, but it is recommended that all belts be inspected at about 50,000 miles and at every oil change after that, to ensure belt rib wear is still acceptable, as well as no failures related to edge cord fray/pop-out and/or rib cracking/chunk-out. The following link is video instructions for measuring belt wear. http://www.youtube.com/watch?v=uFlwqWZvR8Y&feature=player_embedded
Jay Swope, Principle Engineer of Belt Development

 


I understand that Dayco has quality in mind, and I do note that most of your products are manufactured in the US, or Canada. The one thing I do also note is that with pulleys in particular, the most important part- the bearing- are made in China. I understand that high quality must also be tempered with an amount of reasonable cost to product. But a good, high quality bearing that is made in US/Canada can’t cost that much more than one made in china. For example, I purchased a Dayco belt tensioner pulley for that same cavalier. The pulley that was on it before squeaked when cold and for some time until the bearing was warm, I assume. But the brand new replacement Dayco did the same thing. I don’t blame Dayco at all, but I do blame the poor quality Chinese parts used in so many components today. Would you guys considering switching to a US supplier for your bearings?

 

The majority of our pulleys use a ball bearing size known in the industry as a “6203”. The 6203 is the most common ball bearing size sold and is found in many automotive uses. It has become such a commodity item that many reputable manufacturers have ceased making them in the U.S. or Canada because of the economic realities of making them here at the price point now seen. We choose to buy these bearings only from suppliers who can provide the durability and sealing protection needed in our products. Many are still made in North America, but due to availability, some are now sourced outside, if there is no alternative. You can be assured that the bearings used in our pulleys are rigorously tested before going into the pulleys we produce.
Ed Rammel, Vice President Marketing

 


Does Dayco make belts or hoses for the OEM’s, i.e., Ford, GM, or Chrysler?

 

Yes. Dayco is also one of the larger suppliers of belts to Toyota as well as products to virtually every Major Car and Heavy Duty Truck Manufacturer in the World. In fact, Dayco manufacturers tensioners in Springdale, AR that are shipped directly to Lexus Japan.
Robert Christy, Directory of Marketing

 


Is belt wear linear for the entire life of the belt, or does the wear rate accelerate as wear increases?

 

Belt wear will typically be high during the first several hundred miles on the vehicle, as the belt is “seating” into all of the pulleys and is wearing to conform to the system. It will then be fairly stable for rib wear, unless there is slippage in the drive (typically caused by low tensions, accessory/bearing failures, contaminations, etc….). If belt slippage occurs, then the wear rate will continue to accelerate as the wear increases.
Jay Swope, Principle Engineer of Belt Development

 


Does a worn serpentine belt accelerate pulley wear?

 

It actually is the other way around: a worn pulley will cause the belt wear to accelerate. In almost all conditions, the belt will conform to the pulley profile, thus if the pulley surface is not smooth and conforming to the belt rib angles, then the belt rib material will wear until it meets that pulley profile.
Randy Foster, Director of Product Technology/Engineering

 


What causes belt noise?

 

There are two main causes of belt noise: pulley misalignment causing an intermittent belt noise called “chirp” and low belt tension causing a continuous belt noise called “squeal”. For a much more thorough explanation of belt noises, their causes and solutions, please go to www.DaycoW.com.
Jay Swope, Principle Engineer of Belt Development

 


Do you ever recommend belt dressings for noisy belts?

 

No. Any belt dressing may quieten the belt since it will cause the belt to slip quietly, but the EPDM rubber materials will absorb this chemical and cause the rib surface to dry out and typically become more aggressive, which means the belt noise will return (and many times louder than before). Dayco’s recommendation is to determine and fix what is causing the belt to make the noise (permanent fix), thus eliminating the need for belt dressing (a temporary fix).
Jay Swope, Principle Engineer of Belt Development

 


How does your Poly-W technology outperform your older technologies?

 

Dayco’s Poly W belt provides two major changes as compared to our older technologies: 1) a new EPDM rubber formulation utilizing aramid fibers that vastly improves the durability and wear characteristics of the belt, and 2) a “W” tip profile that improves the belt’s noise resistance by allowing the tip to flex and slide (not chatter) when entering misaligned pulleys. When you think about it, an aftermarket belt is put into a much harsher environment that an OE belt. When a belt is put on a car on the OE assembly line, everything about the drive is perfect. Brand new accessories, brand new pulleys and bearings. Perfect alignment. On an aftermarket application, after 70,000 to 80,000 miles, accessories and bearings are worn and the alignment of the belt drive is less than perfect.
Jay Swope, Principle Engineer of Belt Development

 


How does Poly-W technology compare to the rest of the belt industry?

 

Although most all belts now use EPDM rubber in their belt’s construction, Dayco has taken it a step further by developing a patent pending “W” tip profile that is unique to all other poly rib belts in the market. This new “W” tip improves noise robustness by allowing the rib tips to flex and slide (not chatter) when entering misaligned pulleys. Dayco also has other constructions within the Dayco Poly Rib line in order to perform best on certain applications. For example, Dayco engineers discovered that some import application perform best with a belt made with a deeper rib profile.
Ed Rammel, Vice President Marketing

 


On a vehicle that is used only occasionally, what should the replacement interval be for a belt?

 

Dayco’s new EPDM belts are not affected by ozone degradation as compared to the older style neoprene belts, thus time for performance will be extended (to at least 7-10 years as compared to the typical 6 years for a neoprene belt). But, storage conditions can still decrease the time recommended, such as high temperatures, high humidity, and/or oil contamination.
Randy Foster, Director of Product Technology/Engineering

 


If the belt is not glazed and does not appear to be cracked or dry rotted in any way, is there any reason to replace?

 

If the belt is in good condition as stated here, the only other area to check is the condition of rib wear. Dayco has designed an aWEARness gauge for inspecting and determining if the wear in the belt’s ribs are still acceptable. If the wear is still acceptable, then the belt would normally be sufficient for use. For a free aWEARness gauge and video instructions, visit www.daycoW.com.
Jay Swope, Principle Engineer of Belt Development

 


Dayco is now supplier For AutoZone (this was more of a statement than a question – you may want to comment in its validity?

 

Yes. Dayco’s full line of belts, hose, tensioners, pulleys, timing belts and timing kits are now available at Auto Zone. This also includes the Duralast brand of products.
Robert Christy, Directory of Marketing

 


Thanks for being a sponsor. People may hear several ways to know when a belt needs replaced, they may hear to go by mileage, time in use, if the ribs are cracked, the belt is glazed etc. What is the most reliable way to know when it is time to change the belt?

 

The most common method for determining if the belt is ready to be replaced is typically by the amount of mileage the belt has on it. The older neoprene belts would typically last ~50K miles, and it was recommended that the belts be inspected for rib cracking/chunk-out by around 30K miles. Now that today’s belts are EPDM and can last over 80K miles, it is still recommended that the belts be inspected at ~50-60K miles. Since EPDM belts rarely show rib cracking, the failure mode for determining if the belt needs replaced is rib wear. Dayco has designed a new aWEARness gauge to aid in this inspection. Of course, at anytime if the belt shows signs of fatigue (rib cracks, rib chunk-out, extreme and/or asymmetric wear, or edge cord fray/pop-out), the belt should be replaced.
Jay Swope, Principle Engineer of Belt Development

 


Does coolant/antifreeze type have any affects on radiator hose life?

 

Seems they usually degrade from the inside out. Dayco replacement coolant hoses utilize a high quality EPDM tube compound that meets SAE J20R4-D1 requirements. It is also resistant to electrochemical degradation. Unless there is some external damage (rubbing, excessive heat, oil contamination, etc.), hoses will typically fail inside out. This is normal and why hoses should be replaced as part of preventive maintenance to avoid failure.
Randy Foster, Director of Product Technology/Engineering

 


Is there a time limit for preventative changing of timing belts or only a mileage one?

 

Always rely upon the vehicle manufacturer’s recommended intervals in your owner’s manual. If the vehicle has some age on it even though the mileage is less than the recommended interval, replacement should be considered. Some OE shops recommend 7 years. Most Dayco suppliers have this information in their catalog system. Dayco will also have this information included on www.accessdayco.com within 30 days.
Ed Rammel, Vice President Marketing

 


Is there a way to simulate via heat, ozone etc the wear that time produces, and would you be confident in your belts after even 15, 20 years of infrequent use?

 

It is very difficult to determine the cumulative effects of heat, ozone exposure, humidity, etc… in terms of how much time this reduces a belt’s overall life expectancy. Dayco recommends that a belt not be in storage more than ~ 7 years for our new EPDM belts (~6 years for the older neoprene belts) prior to use. Depending upon the conditions during the belt’s service, the belt may run for 6-10 years before the ribs are fatigued or worn and the belt is ready to be replaced.
Jay Swope, Principle Engineer of Belt Development

 


Has new technology, unavailable at the time of engine manufacture, ever been subsequently developed where Dayco would be comfortable suggesting a longer-than-OE-spec change interval? (As an example I believe early VW TDIs had a 40k interval but then later VW made a change allowing longer belt changes.)

 

I am assuming you are talking about a timing belt here. Our aftermarket timing belts specifications are manufactured based on the OE spec so in addition to tooth configuration and belt dimensions, the OE spec also specifies the belt compounds (High or normal temperature) along with the modulus within the construction of the belt. In your VW example above, if the newer models of the VW engine had the same dimensional belt as the older models, but changed the construction specifications of the belt, Dayco would have changed our manufacturing spec to the new and improved materials and would indeed provide the better belt for both the older and newer VW models. That being said, Dayco would never recommend a longer than OE spec change interval on any timing belt drive. With nearly 70% of all timing drives being on interference engines, the risk of timing belt failure and the resulting engine damage is not worth the risk of trying to get a few more miles out of the timing belt.
Randy Foster, Director of Product Technology/Engineering

 


What’s a good cleaner to get that talc/rubber smell off one’s hands after handling new hoses?

 

Being a major belt and hose manufacturer, we actually love that rubber fragrance, but if you find it offensive, normally any good shop grade soap will remove the smell. Many of the citrus based cleaners are quite effective on doing this.
Ed Rammel, Vice President Marketing

 


Can you give a rough estimate of the percentage of Dayco products that are manufactured in the USA?

 

Over 80% of all the parts we sell today are made in the USA. Nearly 100% of all Serpentine belts sold in this country are made in the USA. In the past, we manufactured some serpentine belts part numbers in Canada but since moved production to the States a few years ago. The fact is, off shore manufacturing has been the trend in auto parts in order to stay competitive. We are very proud that we have applied efficient manufacturing practices which allow us to continue to support American workers.
Denny Welvaert, President Dayco North America

 


It’s my understanding that Dayco is an OEM supplier of belts and hoses. Can you comment on any specifications differences of a Dayco provided OEM product vs. Dayco aftermarket product for a given application? I assume Dayco aftermarket line is intended to meet OEM specifications but is standardize to increase value. I must admit that a few times in the past I have observed what appeared to be an OEM Dayco product seems to be better quality than the equivalent Dayco aftermarket. Belts – Dayco’s Poly Rib W belts are manufactured to the same quality and durability standards as Dayco’s OE belts.

 

Dayco’s Aftermarket belt does use a new “W” tip profile, which specifically improves the belt’s ability for noise abatement due to misaligned drives that older vehicles often have. Automotive drive systems on higher mileage vehicles are far from perfect. Replacement belts typically have to contend with slight misalignments and worn components. Dayco “W” belt is an aftermarket engineered solution.
Ed Rammel, Vice President Marketing

 


Does Dayco make any “house” brand belts/hoses? If so, how can a person know which are made by Dayco without contacting the Dayco Company?

 

You can hear all kinds of things at a parts store and many times, it isn’t correct. Our two major house brands (brand names that are owned by Dayco) are Drive Rite® and Dynaflex® by Dayco. In addition, we manufacture the belts that are sold under the Duralast brand by Auto Zone.
Robert Christy, Directory of Marketing

 


Any place in particular that distributes Dayco in Canada?

 

Dayco is the market leader in Canada and you can find all of the locations in Canada by following the following URL: http://dayco.know-where.com/dayco_canada/
Robert Christy, Directory of Marketing

 


On my S-series Saturn I have a Dayco belt and now a Dayco tensioner. How come on your tensioners you use a 15mm bolt instead of the factory 14mm? Also, why don’t you make it the same size pulley as a factory unit?

 

After installation of your tensioner, it was a 2 person job to get the belt on all the pulleys because there was minimal slack. Even both of us struggled to get it put on; it would seemingly be a nightmare to pop a belt on the roadside somewhere. And this was with a belt with 10000 miles so I cannot imagine getting a brand new belt on there with your tensioner. To be fair though, it is running beautifully and I’ve heard the Gates unit would squeal even when new, so it seems I got the lesser of two evils. The 15mm bolt is a commercially available bolt, while a 14mm bolt needed for this application would be require a special bolt at a much higher cost to the end user. Our replacement tensioner has a slight difference in the mounting that requires a slightly larger pulley to accommodate the geometry difference and keep the belt length the same as original. Installing the belt on the replacement and on the original tensioner is felt to be equally difficult due to location in this application. It is not an easy installation.
Randy Foster, Director of Product Technology/Engineering

 


I wish I could talk Dayco to make and sell me, a hard to find, timing belt. Application: A ’94 Cushman Truckster (golf cart vehicle). Has a 3 cylinder, liquid cooled, Daihatsu engine. I need either a 5/8″ Belt. Part# 833452 OR a 3/4″, Part #836962. These are belts with rounded teeth. Gates won’t help me. I hope you are more capable or willing.

 

We are researching this with our European division to identify if we have a replacement. In the mean time, our engineers have researched this part on the web and discovered a part on eBay that just might work. We will communicate information as it develops. Feel free to communicate directly with “BeltGuy” on additional details. The following is the eBay item number and link. Item # 380261768294
Robert Christy, Directory of Marketing

 


Does spray lubricant (such as WD-40 or similar) cause negative effects to belt life or deteriorate the belt?

 

Yes. Any belt dressing may quieten the belt since it will cause the belt to slip quietly, but the EPDM rubber materials will absorb this chemical and cause the rib surface to dry out and typically become more aggressive, which means the belt noise will return (and many times louder than before). Dayco’s recommendation is to determine and fix what is causing the belt to make the noise (permanent fix), thus eliminating the need for belt dressing (a temporary fix).
Jay Swope, Principle Engineer of Belt Development

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