Getting rid of a rattle and looking for tips (maybe exhaust leak?)
11-24-09, 12:24 PM
#1
Getting rid of a rattle and looking for tips (maybe exhaust leak?)
Happy thanksgiving everyone. I have a rattle coming from my car for almost as long as I've had it and I will finally have some time to go after it.
Symptoms: Sounds like there is a tin can or a soda can full of gravel getting shaken around. It mostly happens under acceleration, especially at lower RPMs and the lower gears. When I accelerate, either partial throttle or full it can happen. It doesn't always happen but it does at least half of the times I accelerate. I am not sure if it is coming from the engine bar or under my car. It becomes amplified and much easier to hear when I am driving next to a wall or a wooden fence where the sound can reflect. It also seems to happen when I am cruising on the free way and I downshift to speed up or pass someone, but again not always.
From talking to some people the culprits they have come up with could either be heat shields or an exhaust leak. What is the best way to test if it is these shields and what exactly do they look like. I was told if that is the problem they could be bent or cut off except I don't know exactly what I am looking for. Another person mentioned an exhaust leak but again I don't know how I would check for that. This also seems less likely to me as it doesnt happend all the time and there have been times when I have accelerated from a dead stop and through all 4 gears without hearing it. It seems to happen the most at low second gear though. Being that the sound reflects so well off of walls and stuff leads me to believe the sound is coming from under the car but it may very well be in the bay. I could try and take a video with sound when my sister comes home from college tonight if that would help.
If anyone has any ideas or advice how I could narrow my search down or fix it I would greatly appreciate it. Happy turkey day!
Symptoms: Sounds like there is a tin can or a soda can full of gravel getting shaken around. It mostly happens under acceleration, especially at lower RPMs and the lower gears. When I accelerate, either partial throttle or full it can happen. It doesn't always happen but it does at least half of the times I accelerate. I am not sure if it is coming from the engine bar or under my car. It becomes amplified and much easier to hear when I am driving next to a wall or a wooden fence where the sound can reflect. It also seems to happen when I am cruising on the free way and I downshift to speed up or pass someone, but again not always.
From talking to some people the culprits they have come up with could either be heat shields or an exhaust leak. What is the best way to test if it is these shields and what exactly do they look like. I was told if that is the problem they could be bent or cut off except I don't know exactly what I am looking for. Another person mentioned an exhaust leak but again I don't know how I would check for that. This also seems less likely to me as it doesnt happend all the time and there have been times when I have accelerated from a dead stop and through all 4 gears without hearing it. It seems to happen the most at low second gear though. Being that the sound reflects so well off of walls and stuff leads me to believe the sound is coming from under the car but it may very well be in the bay. I could try and take a video with sound when my sister comes home from college tonight if that would help.
If anyone has any ideas or advice how I could narrow my search down or fix it I would greatly appreciate it. Happy turkey day!
11-24-09, 04:33 PM
#2
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My sc400 does that too. mine seems to present itself when cruising and I let off the throttle just a little. I crawled under the car and checked the heat shields in front of the cats. The one on the pass. Side moved a little. So I pulled it downwards. It Stopped the rattle. But it is slowly coming back.
11-24-09, 04:49 PM
#3
1JZ Single SC400
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I would also say the exhaust shields, they are known to cause rattling and man are they annoying. Just jack up the car and start it, and hit them with a rubber mallot, and see if they move or make a sound at all. Make sure to check both sides. Good luck and keep us posted on what you find.
11-25-09, 12:52 AM
#5
I would also say the exhaust shields, they are known to cause rattling and man are they annoying. Just jack up the car and start it, and hit them with a rubber mallot, and see if they move or make a sound at all. Make sure to check both sides. Good luck and keep us posted on what you find.
..I had this same annoying issue. Its just a piece of metal welded to your exhaust piping where it comes near another part of your undercarriage. Its just to protect that other part in case your piping gets too hot. Over time the welds will break resulting in the shields rattling. Theyre not ALL that important so just rip whichever one is loose off. I ended up ripping 2 of mine off from my old sc. No more rattling.
11-29-09, 04:35 AM
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I had the same problem as you. In my case, it was my cats because the time smog came around I failed. I decided to replace my cats and literally the insides of the cats were tore up. I haven't heard crackling or rattling since.
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12-05-09, 02:18 PM
#12
Ah sounds good to me 
I just didn't know if there was something about Florida that would wreck my cats faster or something. Is there any way to check if they are bad my self while on the car or would I have to take them off and shake them around or something.
I just didn't know if there was something about Florida that would wreck my cats faster or something. Is there any way to check if they are bad my self while on the car or would I have to take them off and shake them around or something.
12-05-09, 09:43 PM
#13
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if the cats are bad/clogged, your CEL should turn on and you should feel a drop in performance...if they're beaten up, then you will hear some rattling as you gas it.
different kind of rattling between bad cats and exhaust leak....you have a sound clip?
different kind of rattling between bad cats and exhaust leak....you have a sound clip?
12-06-09, 07:07 AM
#14
I don't have a camera at the moment with video capability so no sound clip but I will try and find one asap. This rattle is only under acceleration. It also seems to be the loudest when I press the gas and accelerate but not enough to make it down shift. The check engine light is not on and it the car seems to be running fine.
04-09-10, 02:46 PM
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Did anyone come up with a final solution? Mine is doing the same thing-- rattling noise when on freeway and backing off accelerator and this morning when starting cold is was very noisy and then quieted down a lot when warmed up. My '94 SC400 has 80K miles in California.