Just replaced my belt with Goodyear 4060578 recommended my other members. The position of the indicator still falls out of spec, probably only a little bit better than before. What's worse, when I started the car, the indicator fluctuates, it didn't do that before replacing. Should I replace the tensioner or there is something that I should tighten? Any idea? Thanks!

 

The indicatior on the tensioner is useless. Don't worry with it. A quick visual inspection of the belt is really all that needs to be done to insure it is in good condition. The fluctuation you are seeing on the indicator now will go away after the belt has broken in a little.

 

Thanks a lot, your reply saves me 110 bucks!

 

You can't tell a belt's condition by looking at it--that ability ended years ago....

The old neoprene serpentine belts used prior to the late 1990s cracked when they wore out but the EPDM ones used since 2000 rarely do even when they're worn out....

http://www.gates.com/products/automo...-vs-epdm-belts

Here's how to check whether your tensioner needs to be replaced....(scroll to the bottom of the page)

http://www.gates.com/products/automo...wear-diagnosis

 

Obviously you can tell a epdm belt's condition by looking at it, there are pictures in the link you provided.

 

Reading the words in addition to just looking at the pictures is necessary......it clearly states that the loss of 5% of the belt's rib depth can be cause for replacement. This is not something that can be seen ---it must be measured.

You cannot tell an EPDM belts condition by looking at it. If it looks like the pictures, it should have been replaced 10's of thousands of miles previously.

I grew up leaving serpentine belts on the car til they showed cracks. They were the old neoprene ones. That's not wise practice anymore with EPDM belts. That's why I use a belt gauge--it's a small plastic tool that costs a buck or so. It fits into the ribs on the belt to measure whether the ribs have worn down enough that the belt should be replaced.

Things change over the years so I follow the belt manufacturer's recommendations---and advise others to do so as well.

 

Thanks for your links, they are very useful. I attached a photo of the indicator after replacement (goodyear), compared with OEM belt(I do have a brand new OEM belt that I bought before and I planed to use it on my another s2000), the goodyear feels thinner, so actually I swapped it to the OEM belt later in the afternoon.

The tensioner still vibrates and definitely visible to my eyes. The indicator goes a little bit forward, just on the edge of the notch, I don't know why it doesn't go any further. I tried to examine the condition of the tensioner by rotating it, the gap marked by two red lines became larger. I'm not sure if that's normal. The car has 79k on the odo.

I really hope the vibration is caused by break in, otherwise it doesn't make sense since it didn't do that before replacing.

[attachment=58848:Untitled.png]

 

I'd recommend driving it a few days and see if the tensioner stops vibrating ( the belt may or may not need a break in period-- the old ones did-- not sure about the new ones.).

If it still vibrates then, you'll need to replace it

 

Goodyear 4060578 on my car is within spec with about 25% tolerance. It's definitely a little larger than OEM.

edit: running it for over a year now, 15k miles at least with no problem.