02 Honda Civic SiR.


Video of tensioner pulley while engine idling

Tensioner alignment marker with engine off:

Tensioner alignment marker with engine off

A bit more info:

  • tensioner pulley has been replaced less than 2,000 KMs ago
  • belt was replaced at the same time
  • I hear a pulsating humming/rubbing sound (stethoscope hears it loudest from the tensioner pulley)

The tensioner pulley replacement was a Gates unit. Should I try and replace it with the Honda OEM pulley or just replace the whole tensioner unit? Or should I be looking at something else entirely?

  • Replace the tensioner with a new unit, it should come with the pulley.
    – Moab
    Commented Feb 15, 2019 at 16:25

1 Answer 1


Absolutely you'll see it bouncing slightly. The reason is, the belt will stretch and contract slightly as the engine speeds up/slows down. The tensioner provides two different functions:

  • Provides tension to keep the serpentine belt tight during operation
  • Takes up slack which might be introduced as the belt gets older

Well, there's a third thing to consider, as well:

  • In a lot of vehicles, helps keep the belt in alignment

Tensioners should be good for well over 100k KMs (and most likely a lot longer than that). After just 2KKMs, you shouldn't have a fear about this ... even the bearing. The belt should be good for somewhere around 100KKMs (but check the belts manufacturer's recommendations). There are even higher quality ones made with Kevlar which will last even longer.

As far as the noise ... those are turning bearings in there. You will hear some noise!

You really shouldn't have any fear of what you have as long as it was installed correctly. I'd assume since you've made it 2KKMs without real issue, there's not going to be. The tension markers seem to be aligned correctly, which makes that good to go as well.

  • Thanks Paulster. The car as 182K KMs, but I have no idea what's been replaced on it before I bought it used. It's worth clarifying that the tensioner unit itself was not replaced, only the pulley. The work was done by a shop, I double-checked the torque on the pulley bolt as well. I have replaced the idler pulley with an OEM unit, which is clearly better manufactured than the aftermarket Gates unit that was on there previously, so I may just replace the tensioner pulley as well to get rid of the annoyance. Commented Feb 14, 2019 at 14:58
  • @RecoveringNerdaholic - The tensioner may need replaced, but as long as it is keeping the markers within proper alignment, I'd suggest it's still doing its job. Commented Feb 14, 2019 at 15:00
  • @Paulster2: thanks. I haven't seen the marker move outside the range (although the manual states it shouldn't move at all?). Also, the first video link in my post is wrong, I've corrected it. Commented Feb 14, 2019 at 15:10
  • @RecoveringNerdaholic - The flicking the tensioner is doing in the video is nothing (and when I say nothing, really it is nothing). Just normal operations. Commented Feb 14, 2019 at 15:17

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