Trying to figure out this pulsating rubbing/humming sound in my Civic Si/SiR

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5 days 4 hours ago - 5 days 3 hours ago #201455 by 02EP3
So, I just checked and I notice that the tensioner pulley can be jiggled by hand, with the belt on. I wonder if the shop under-torqued the pulley bolt (I've had to "clean up" after them before).

Before I go spending money on parts, I'd like to try and torque it to spec. Two problems with that:

1. The space is too tight to fit a torque wrench. I might be able to get in from underneath, or use the extension on my belt tool (although that will change the torque dialed in and I don't know the math on that). EDIT: I may be able to just figure this out using the idler pulley bolt to check the torque setting with the extension and compare, since they're both 41 ft/lb.

2. How can I torque it down when the bolt torque (41 ft/lb) exceeds the spring torque (27 ft/lb)? I don't see anywhere to lock the tensioner. I guess I could just let the tensioner move to the end of its range, and then torque down the bolt, but I don't want to wreck it.
Last edit: 5 days 3 hours ago by 02EP3.

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5 days 1 hour ago #201463 by relative4

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5 days 32 minutes ago #201466 by 02EP3

relative4 wrote: Pics might help.

I'll try to get some tomorrow. Cold as balls out there today :P

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4 days 16 hours ago #201478 by hondaguy453
The pulley on the tensioner wiggles around? Usually the pulley itself doesn’t get removed from the tensioner. Also, there should be marks on the tensioner body which tells you if the tensioner spring has lost its ability to retract. Usually three marks on the one side of the body and one on the other side. The one mark should line up perfectly with the middle mark on the other side. The other two marks are thresholds for the tensioner spring. If the mark is outside of those, then the spring is faulty and the tensioner should be replaced.

As for torquing the pulley, be careful. I can’t remember if there is an access hole to lock the tensioner, so if you’re going to torque the pulley bolt without it, be careful.

You’re sure the noise isn’t coming from inside the timing cover? There is a black cover near the rear of the crank pulley. This is where the timing chain tensioner is and could be what is causing the noise. Remove that cover, if that is in fact where the noise is coming from, and check to see how far out the plunger is. It shouldn’t be too far out. Also, with the cover removed, you can spin the engine by hand to see if the plunger moves. You should also check the timing chain guide for wear, as this is why the plunger is all the way out.

If it ain't broke, don't fix it
A1, A6, and A8 ASE Certified
The following user(s) said Thank You: relative4

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4 days 6 hours ago - 4 days 6 hours ago #201483 by 02EP3
Thanks for all the helpful info, hondaguy.

The pulley for this tensioner is replaceable on its own. I have a PDF of the service manual for this car, which confirms that, but doesn't give any advice on torquing it down other than the torque spec.

The tensioner body itself doesn't move out of spec. However, it does bounce around slightly (maybe 1mm) at warm idle.

The noise definitely sounds rotational and I'm quite certain it's originating from a pulley. I'm going to try and get my stethoscope on all the pulleys and on the timing cover this afternoon.
Last edit: 4 days 6 hours ago by 02EP3.

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3 days 23 hours ago - 3 days 22 hours ago #201488 by 02EP3
Alright, I did all the troubleshooting that I could think of:
  • Slipped off the belt, spun tensioner pulley by hand. It's a tight fit getting my hand in there and I can't really spin it fast enough to hear anything. But, the side of the pulley facing the engine appears to have some imperfections (ie.: it's not perfectly smooth).
  • Timing cover sounds like normal, quiet metallic sounds
  • Put the stethoscope on every pulley and accessory I could with the engine running. I'm not sure if I got the water pump, because it's buried deep in there and I can't really get at it without a hoist.
  • Put the stethoscope on the idler pulley bolt, tensioner pulley bolt and the tensioner unit while revving the engine by hand. It's clearly loudest on the tensioner pulley bolt.

Edit: pic of alignment markings while engine is off.

Last edit: 3 days 22 hours ago by 02EP3.

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3 days 16 hours ago #201491 by hondaguy453
Sweet! That mark on the tensioner looks perfect. It does sound like that pulley may not be torqued, or the bearing is just jacked up.

If it ain't broke, don't fix it
A1, A6, and A8 ASE Certified

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3 days 8 hours ago - 3 days 7 hours ago #201496 by 02EP3
Great, thanks! Now how I actually torque it down without damaging the tensioner spring? Also, I think I did mention that the tensioner bounces around a bit at idle, but I wonder if that could be caused by bad pulley bearings or a under-torqued pulley.
Last edit: 3 days 7 hours ago by 02EP3.

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