Seam on serp belt, normal or not?

[01rangerxl]

I've noticed a seam on the Dayco Poly W serp belt on my truck where I can see fiber stitching. It has been like this since installation as far as I know. I did not look the belt over completely before installing it, and noticed this seam sometime afterwards (maybe 1K miles). The belt has maybe 6K on it now and the seam looks the same, but is more noticeable than on the Dayco Poly W it replaced.

New belt...

It's hard to see in the pic, but up close in person you can see fiber stiches that go diagonally across the belt.

Old belt...

You can see a line where the diagonal seam runs, but no visible stiching. That belt had maybe 38K miles on it and was replaced because it sqeaked if I turned sharply.

The diagonal seam is obviously normal, but I don't know if being able to see fiber stiching is. I don't really want to replace it again if this is normal, but I don't want it to come apart and possibly damage something either. I've never paid this much attention to a serp belt, the line just caught my eye.

 

[Nick1994]

I've seen this on belts before too. Have no idea what it's for.

 

[user52165]

I've always considered Dayco a poor alternative to Gates, Goodyear, Conti, Bando, OEM, etc.

 

[doublebase]

I think you having to change a serpentine belt at 38k miles is strange to begin with...why go back to that brand?

Personally I've never noticed a seam like that before, but then again I don't usually visually inspect new belts, aside from matching up the length to the old one. These things are supposed to last longer than 38k miles - I wonder if you have an idler pulley with some sort of bur on it? I know that the ribbed side of a belt are no longer inspected for cracks - because they are designed not to crack anymore - but rather are inspected by a gauge that measures rib depth.

 

[Boomer]

When I worked, we made belts at one of our plants for spinning machines...some small, some large. These were made by winding the appropriate cord like Kevlar around a drum, then impregnating uncured elastomer into the cord. The entire drum (maybe 60-72" long) was put in an oven and cured. When done, this 60-72" "belt" was slid off the drum and then belts were made by cutting to the correct width, like an inch or so. The belts produced were therefore seamless. There was NO seam like you show across the belt. I have no idea why a seam should exist like this.

 

[ragtoplvr]

Yes it s normal, this belt incorporates a layer of rubber impregnated cloth on the back side. Under that are the cords, that can be different materials depending on if it is stretch or common belt, then the grip rubber ribs. The cloth adds sideways strength to the cords. There are many ways to make belt, this is one.

Rod

 

[tom slick]

I've seen seams before. Looks normal to me.

 

[cjcride]

You could contact Dayco customer service. E-mail the picture to them see what they think.

 

[01rangerxl]

Originally Posted By: doublebase
I think you having to change a serpentine belt at 38k miles is strange to begin with...why go back to that brand?

Personally I've never noticed a seam like that before, but then again I don't usually visually inspect new belts, aside from matching up the length to the old one. These things are supposed to last longer than 38k miles - I wonder if you have an idler pulley with some sort of bur on it? I know that the ribbed side of a belt are no longer inspected for cracks - because they are designed not to crack anymore - but rather are inspected by a gauge that measures rib depth.



I went with Dayco for the price and because it was immediately available. The old belt wasn't shot, but it would chirp on some sharp turns, so I went ahead and put a new one one.

But yes, I probably should have gone with Motorcraft, as I have gotten over 100K out of one of those and only replaced it as PM.

I might email the pic to Dayco and ask them if threads being visible on that seam is normal.

 

[Robenstein]

At least your DAYCO fit. So you have one up on me there off the start. Bought one for my 2.4 Scion and its way too short.

 

[1kickbuttranger]

Originally Posted By: 01rangerxl


But yes, I probably should have gone with Motorcraft, as I have gotten over 100K out of one of those and only replaced it as PM.

I might email the pic to Dayco and ask them if threads being visible on that seam is normal.


The replacement Motorcraft belts are nothing like the original factory belt. I stick with Gates.

 

[zzyzzx]

Are you sure that you don't have some other issue causing the chirping on turning? You know like using a belt that's a little too long, or you have a weak tensioner spring, or a pulley issue.

 

[01rangerxl]

^ It stopped with a new belt.

 

[BrianLWheeler]

Hey everyone! Brian from DAYCO here.

You are correct. The belt should not look like this. If you would like to run DAYCO again, I'd be happy to send you a new belt, free of charge.

What do you think?

Brian

 

[01rangerxl]

Thanks for responding Brian and for your offer! I will send you a message.

 

[01rangerxl]

Hi Brian,

I sent you a private message because I didn't want to post my address on the forum, but it's showing as unread. You can get to the private messages by clicking on the envelope icon at the top of the page, or clicking on the "My Stuff" menu while logged in.

Thanks again!

 

[GMBoy]

I have used DAYCO brand belts for years and always been satisfied. Strange thing is for that mark to be on your OLD belt and the new. Seems like there is something going on that is making this mark like a burr or something on the pulley as someone else mentioned.

 

[01rangerxl]

I would expect that kind of damage to be repeated in multiple places on the belt, not isolated to one spot that hasn't changed. I would also expect that kind of damage to show some other way than a single diagonal line (horizontal line, repeated pattern of diagonal lines).

Everything in the belt drive is smooth and quiet.

 

[Gokhan]

That doesn't look normal but it shouldn't be a big concern unless it's deep or starts to fray or gives other problems.

 

[berniedd]

I have something similar on an original serpentine Honda belt in my 2 yr old CRV that was a direct import form Japan. Just keep an eye on it from time to time. I don't think either of us has cause to be worried about it.