Exhaust Rattles?
 

I believe it's my catalytic converter that rattles.
Every time I start my car, drive at a low RPM, or a slow take off at a traffic light
It sounds like there are rocks in my catalytic converter

Any suggestions what it is?

Thanks

The heat shield around the catalytic converter can rattle. Mine had a crack where the two halves bolted together.

If you find that this is the case, you can use a large hose-clamp to help keep it together or replace the heat shield.

Yea I already checked that...I thought the screw were loose or something
but the heat shield seems fine & I checked along the exhaust piping & nothing loose or cracked....

Check the A-pipe, your car should use #7 (instead of #8). See if you can tell exactly where the noise comes from. Some years that A-pipe is a double-walled pipe, and the inner pipe can buzz against the outer pipe.
http://www.hondaautomotiveparts.com/...13S840_B02.gif

If it's actually the converter (internal catalyst crumbling?), you should be able to hit the converter & make it rattle, with the engine not running. The buzzing A-pipe is nasty, because when it happened on my 95 Integra there was no way I could duplicate the noise by banging on anything. It was caused by the motion of the engine under acceleration. I wasn't willing to hang under the car while it was actually running down the road...

Thanks I'm gonna give it a try sometime this week....
(Will you able to hit the catalytic converter with the heat shield)

But it is the A-Pipe just like you said...is it a pain to take the A-Pipe off?
Cuz I know taking the catalytic converter off is a pain in the butt

Hitting the flanges at each end of the converter usually gets it to rattle (if the ceramic core is crumbling). But those cores are more robust & don't fall apart like the ones they used 30 years ago.

Taking off the A-pipe is theoretically easy. But usually the nuts & bolts are all rusted & need a couple hours soaking with PB Blaster. Then they often break anyway. Get new gaskets (#10 & #17). I usually have all new bolts so I can remove the old ones with a sawzall when the wrench doesn't work.

If you leave the converter bolted up to the "B-pipe" (#14) then you'll want to use a jack or something to support it.

The whole exhaust system grows longer as it heats up, so when cold, you have to stretch the rubber hangers to get it lined up.

Those are the kind of difficulties you'll run into.

I SEE O.O
Good thing I don't have the B-Pipe which I've never seen one before....

Do you think it's easy to remove the bolts using an air tool or a cordless power drill?
But either way the bolts need to soaked with lubricant, correct?

Thanks

Oh I got a quick question....when I was checking my heat shield for the catalytic converter & making sure it was tight I broke one of the bolts so I just remove the heat shield...
So does it do any harm if I remove the heat shield?

You must have a B-pipe, it's the next pipe after the cat. It's #14, the long pipe with the middle muffler in that drawing...

If you live in Arizona where it takes 100 years before anything rusts, then maybe the bolts will come off easy. You'll never know until you try.

Lots of people have removed the heat shields from their cats. But you have to be aware if you park over dried grass or leaves, you may start a small fire... And the upper part of that heatshield protects the underside of the car from getting too hot if you idle the car a lot.

Heat Shield
 

I just experienced a similar problem with my heat shield. It was hanging and actually dragging on the ground. I ended up snapping it off; it was only being held by one bolt. All of the bolt locations are completely rotted! I'm surprised since the car only has 78K on it; it could be due to living in New England (salt, sand,etc...) I ended up wrapping wire around the cat to hold the top shield on, for the time being. I plan on replacing the shield myself and was wondering if anyone knows how much of a hassle this is? Does the top shield come out or do you have to drop the exhaust? Any feedback would be appreciated.

Thanks,

Did you keep the lower part too? You can put it back on & use hose clamps to fasten it.

I have a similar problem.

I had the heat shields come loose at the bolts and now have two metal clamps on them. I always wondered if the fact that the shields are now making contact with the converter, if the heat is transferred on and therefore can still start a fire.

I've had the entire exhaust pipe (from the catalytic converter to muffler) replaced just recently. However, whenever I'm at a specific range of RPM (either right when I'm starting to drive before it advances to second gear and then again in between 2nd/3rd gear), it sounds like the area between the catalytic converter and the A-pipe rattles like crazy. I also noticed that if I warm up the car, this happens almost immediately rather than if I driver her off "cold". I can usually manipulate the rattling with the gas pedal - taking it off or pressing it at the right time for it to change - for example: I drive up a hill, top of the hill that area begins to rattle, down hill I let go of the gas (feel the gears change) and the rattling stops. It's gotten worse. Whenever doing highway speeds (70 mph), now there's a constant low pitch rattle/grind like there wasn't before.

I posted about this issue before and it was suggested that it might be a cracked exhaust manifold - my visual inspection didn't find a crack or anything as far as I could tell.

Thanks

CAT Heat Sield
 

Instead of messing with the old shield, I just purchased a new one(top & bottom) and 4 new bolts. With shipping and handling, it came to roughly $53. The old shield was rotted away at each bolt location. I thought about welding it or clamping it, however, I opted to just replace it. I may have to lower the exhaust to get the top cover on. I'm going to be tackling it this week and will post my results.

You'll probably have to remove the 2nd O2 sensor, which (I think) installs thru a hole in the upper heatshield. I think you need to go underneath the front passenger seat to unplug the wire for that.

I had the same problem when I bought my 94 accord, its the gasket where the headers merge to the catalytic converter. I was going to tighten the bolts but they were rusted to the point where it might strip the threads, so I decided to clamp it with a vise clamp. If youve got a vise clamp lying around, tighten it as much as possible and squeeze the flanges together where they meet. I thought it was the heat shield or the cat, but it was definately the gasket, because after I clamped it, no rattling noise! Its lasted since then for a year and a half. And it only happened at 1800 rpm, quite loud too (enough to be embarrased by). Dont use a spring clamp, theyre not strong enough to stop the vibration.

Let me know if it stops the rattling noise, if it doesn't then its not the gasket, could be another part of the exhaust.