Mystery Rattle

[ginnai]

I am getting a rattle in the engine compartment between 1500 and 2000 rpm. Once the car warms up, it disappears (I assume something expands and snugs up). After looking at some threads, I replaced my belt tensioner pulley... to no avail. AC clutch seems fine and everything turns smoothly (alternator, water pump, tensioner)... but I still get a rattle. At some point, I am just going to tear apart that side of the engine... anyone have ideas?

[Dave_The_BMXER]

Passenger side? Does it depend on load? Is it really loud on cold days?

If so I might have the same issue... my pulley has been replaced too.

[ginnai]

Yep. Passenger side. In terms of load, do you mean N vs D? If so, then yes under the load of the transmission is the only time it is heard. Also the cold does make it worse. So you replaced the tensioner pulley too? I didn't mention it, but I have also tightened down my heat shield... but no change. Replacing the entire tensioner is probably my next step. Have you tried to listen for it under the hood? The sound seems like its from the accessory belt, but I really can't pinpoint it. It is affected by heat, so something warms up/ expands and the noise is gone. The noise sounds like it is rotational, so my bet is that it is a part that spins... which is why my first thought is still on the tensioner. It is driving me nuts, so if you get this figured out... let me know!

[Dave_The_BMXER]

Oh you are auto. By load I mean under hard acceleration like up a hill or something but it might be a little different in auto.

Mine sounds rotational too.

[ginnai]

Yep, but the engine load would still have the same effect. My thought is that the load torques the engine and the tensioner mechanism is failing... until it warms up and the (spring/ internal mechanism) expands. Other than that, I can't think of anything that rotates in that area or would be altered by acceleration. At this point, the $200 tensioner isn't really worth it as we enter summer I will just keep track of it. Worst case scenario is the tensioner spring/ mechanism fails and the noise gets worse. Until then I will just slowly be driven insane. If I can find a lower price, I may just change it out... but I dunno if you have looked at your's, but my tensioner is still within the range of function. Anyways, I am just venting thoughts I have had for a few weeks. Let me know if you agree/ have other ideas.