0Steve@AandACorvette

I get asked quite a bit about how long a belt will last and how do you know if the belt needs to be changed. We have been working with Gates to help educate our customers on the serpentine belt, which is a critical part to a supercharger system.

EPDM belts, installed by original equipment manufacturers on new vehicles since the late 1990s, typically do not show obvious signs of wear, as with Neoprene belts. Cracks and chunk-outs rarely occur, so it is necessary to evaluate belt wear differently. Like tires, EPDM belts wear out gradually, steadily losing rubber material.

NEOPRENE VS. EPDM
Older Neoprene belts have a life expectancy of 50-60K miles, and as they wear out, cracks and chunk-outs will occur, as shown below. EPDM belts rarely show these symptoms, even at very high mileage.

As EPDM belts age, they gradually lose rubber material—similar to the way tires wear out. Over a period of 100,000 miles, a belt can lose up to 10% of its rib material. While this may not seem like a lot, the consequences can be significant.



EPDM: SIGNS OF WEAR
The diagram below shows how EPDM belts wear as they age. Although the ribs have not become shorter, material has been lost in the valleys of the ribs (indicated in red), making the space between ribs wider. As more material is lost, the pulleys ride deeper into the belt valleys resulting in slip, noise and hydroplaning.

With sufficient material loss, the pulley ribs “bottom out” in the valleys and ride on the belt cord. This reduces the surface contact on the valley sides, where the traction is generated. Wear also increases the effective belt length, lowering the tension in the system, which also reduces traction.



OBVIOUS SIGNS OF WEAR
Although EPDM belts do not tend to crack with age, they can still exhibit other symptoms that are caused by problems with the accessory drive—such as tensioner misalignment or failure, pulley misalignment, excessive heat, or bearing failure in one of the other components.

If the belt exhibits one or more of the symptoms depicted, it needs to be replaced. If it fails, it could damage other system components in addition to stranding the motorist. Many warranty-claim failures on alternators and other parts are actually caused by worn or improperly adjusted belts.



OTHER BELT WEAR SYMPTOMS
When a belt wears out, several problems can occur that reduce performance of the Accessory Belt Drive System.

BELT SLIP–LOSS OF TRACTION
Like a tire, a worn belt can lose traction (slip) on the pulleys, particularly in high-load and/or wet conditions. Slip can cause belt/pulley temperatures to rise by up to 50%—leading to early accessory bearing failure.

HYDROPLANING
This occurs when water cannot be effectively channeled away between a worn belt and the pulleys. The belt then “hydroplanes” on a film of water, resulting in loss of power transmission to the accessories. This can often result in the “Check Engine” or “Alternator Charging” warning lights to come on.

ELONGATION
Material loss can also cause a change in the effective length of the belt, which can move the tensioner beyond its take-up range. This will reduce overall system tension, also lowering accessory performance.

MISALIGNMENT
Misalignment wear can also be an indication that the internal components of the tensioner have failed. Material loss and subsequent changes to effective length on belts can also cause belt slip, resulting in noise, vibration and high heat, which can damage accessory bearings and cause accessories to fail.

Gates has developed a Belt Wear Gauge to help you and us assess wear on these newer EPDM belts. It is simple to use, and will allow you to quickly gauge wear on a multi-ribbed serpentine belt–either on the engine or off.





If you would like one of these, please PM or email me.

csun213

Generally how long are the belts good for? Should we replace them at 15K or 30K etc?

TRIZ

Thanks Steve.
Good info.
EPDM = Ethylene Propylene Diene Monomer.
Except in Steve's special case: it's Moronomer instead of monomer.
EPDM has good abrasion and heat resistance, but poor oil resistance.
I used to work at Dayco, a competitor of Gates.

NYC6

Good info to know, thanks

PowerLabs

You can't really give a generic answer to that since belt life depends so much on the tension and stress on the belt, which depends enormously on pulley size and how hard the car is driven...
But for what its worth, mine came out at 30,000 miles with zero slip and looking new. 3.8" pulley.

0Steve@AandACorvette

Like powerlabs said, it's hard to give a solid answer. I would check the belt first at 5K or one six months with the gauge and see. Then maybe check it once a year. Also look for the other signs of wear as well.

obzidian

One thing that I don't understand is that folks have mentioned how they had horrible belt issues with a blower/pulley setup that wasn't to radical. I wonder if this is due to poor belt life or poor belt maintenance or just the use of cheap napa-belts I.E. neoprene.

Boat Racer

Good info. Email sent!!

aTX427

Gates was offering their belt wear gauges for free a while ago. You can order one from their website.

0Steve@AandACorvette

I am not charging for these... and you can get them off the gates website as well. I have a bunch here from my Gates rep that I am going to send out. Then I'll either get more or send people the link to get one.

0Steve@AandACorvette

Bump for the newbies to the forum and Forced Induction.

0Cunningham Motorsports

all the napa belts i have used have been made by gates

Robls6

I've got 10,000 miles on my belt (A&A kit) and there are what appear to be small lines developing in the top of the belt. Alignment is fine and the edges of the belt are fine, but these lines are starting to worry me. I haven't replaced a belt yet but I understand it's kind of a PITA with the A&A kit?

0Steve@AandACorvette

It can be a bit challenging if you haven't done one before.

Robls6

Seriously???? The whole blower has to come out to change the belt??!! How did you tighten the belt? There has to be an easier way than that?

MARSC6

I had a gates belt from Napa slipping after about 1500 miles in 1 year. Put the car away for winter working fine but the following spring I couldn't more then 5-6psi until I changed the belt.

timschot

The "whole blower" is like 3 bolts. Or at least it is with my procharger setup. Not a big deal

Robls6

I suppose it looks harder than it really is. I'll find out soon I suppose.

TRIZ

Thanks for the video Steve.
I'll have to try that someday!
and please tell James " and that's how you eat a turkey" by Martha Stewart.

RareSS9596

The biggest challenge for me would be getting my son and wife to drop the car off at The Vette Doctors. Sometimes it pays to let someone else do it.