Low RPM buzz/vibration after Timing Belt Change---What did I do wrong?

[shackelton]

I replaced the timing belt, tensioner & idler pulleys, and the tensioner spring on my '92 with 156k miles. The belt was done once previously.

While I had it apart I also replaced the front lower motor mount & the torque axis mount. Also replaced the front crank seal, the camshaft seal, and the oil pump cover gasket and seal. Finally new drive belts (P/S & A/C-Alt) along with new OEM plugs, wires, rotor and distributor cap.

The timing marks were set dead-on. the timing checks out with a timing light. It starts great, and runs great....above low idle that is.

There is a very pronounced vibration/rumble at idle. It dissappears as soon as I give it throttle.

I put my hand on the motor while it is idling and it feels OK. I did notice that when I blip the throttle WITH MY HAND ON THE A/C compressor it feels like the compressor is the source.

But when I took both accessory belts off and ran the motor without both, then just the P/S belt, I couldn't tell a difference.

I'd almost swear the buzz in coming from the lower front (timing cover end) of the motor.

What can I do short of taking it all apart again? I don't want to damage the motor!

Thanks.

[shackelton]

Any ideas befire I pull this thing all apart again?

From inside the car, it sure sounds like a buzzing exhaust pipe. I have inspected the pipe from the manifold to the tailpipe and can't find anything loose, binding or leaking.

It seems to get a little quieter when it warms up (low temp has been 20 deg. F).

Thanks.

[Nick]

too abstract to diagnose without being right there man

[seraslibre]

I have the exact same problem. Only that for me, the vibration/sound disappears after 2k rpm. It does not slowly disappear, but immediately just disappears at 2k rpm. I personally think its the belt that i used. Made the mistake of going to Strauss Automotive and got a no-name belt. It may also be the rubber gasket seal that keeps the belt cover sealed and also works as a sound insulator. Some strips fell off when I made the change.

[Hambone]

I have been getting a similar noise. I was thinking water pump but can't seem to nail it down and no one seems to have an answer.

[seraslibre]

BTW.... i also changed my water pump when i swapped the belt. It was a reman. toyota pump.

[shackelton]

hmmmm....I replaced the timing belt with a Toyota OEM. I also replaced the timing belt cover gaskets because they came off in pieces when I disassembled it.

Last night I had the car running, in gear, with the emergency brake on. I was able to reproduce the noise by applying a little throttle, and it is definitely coming from the timing belt area.

I am going to take the top half of the timing belt cover off this weekend and see if that in itself cures the noise, or at least get a look at the belt install and see if anything is up there.

Thanks for the feedback guys

[hughyii]

Did you ever figure out where the vibration was coming from? I just changed my timing belt and have the exact same symptoms. Plus I have a squel when the A/C turns on but that is just the new alternator belt that needs to be tightened. Like you , I swear it was coming from the timing belt cover.

[csaxon]

The OP posted this thread almost 7 years ago, although I think he's still around. Try PMing him,