Noise coming from exhaust..might need to replace catalytic converter

[vishesh]

I have been hearing a rattling sound from my J for the past few months, and took it to a few dealers / mechanics to get a diagnosis. The concensus is that it is caused by a hole in the exhaust system somewhere between the exhuast manifold and the catalytic converter. I haven't seen any posts about this in NICO, and I've got a few questions:

1. Would/could this affect performance / mileage / driveability? I don't know that much about cars in general, but this shouldn't have any adverse consequences, right? One of the mechanics said it shouldn't, and I am inclined to agree with him. I think it might just make the car noisier and pollute a little more. But I'd like your opinions...

2. All shops said that the part is only available from Nissan, in which case, it would be very expensive (especially given that it may just be a superficial repair--depending on the answer to part 1). I'd like to save $$ by getting the part refurb'ed (maybe from a junkyard / ebay / parting out), but my question is: can I replace the catalytic converter / pipes with used ones or do I have to replace with a new one? (Obviously, the gaskets would have to be new)

3. I was looking for the list price of the part on Carlos' parts list, but I can't find it. The parts list shows the resonator+piping and the muffler, but doesn't list the catalytic converter+piping, at least, I haven't see it.

Anyway, if you guys have any thoughts, I'd appreciate it. My goal is to a) save some money by doing it myself (if possible) and with used components and b) to learn something in the process.

[yodawill2000]

Someone last week had a rattle down there and it turned out to be a loose heat shield by the Cats , Or sometimes some gravel can get between the shield and the exhaust and rattle like crazy . A hole in the exhaust wouldnt make a rattle sound I wouldnt think.

[vishesh]

I should probably clarify...it's more like a growling, not really a rattling. I don't hear the growling much at idle, but when I rev it (even in park), I hear the growling increase in volume. So that's what made me initially suspect the exhaust system.

[vishesh]

Also, here is a diagram from the service manual. I've highlighted the segment of the exhaust that the mechanic told me needed replacing.

[DominickJ30]

You wont be able to do this yourself unless you have a welder. And they were right, its not a heat shield but rather a hole probably right after the cat. I had the same thing with mine.

Best bet is to take it to a custom exhaust shop and either have them weld in a new pipe in that section, or get a whole new custom exhaust.

I think the tube size is either 2.25 or 2.5"

[driverdriver]

[QUOTE=DominickJ30]

Best bet is to take it to a custom exhaust shop and either have them weld in a new pipe in that section, or get a whole new custom exhaust.

QUOTE]

A custom exhaust on the may cost you more than OEM. Get some quotes before you commit one way or another.

[vocoder]

i had the same problem. especialy when i am accelerating or braking.what i did?

i bought mufler straps at "Murrays Auto Parts" around $3-$4and i did as show on picture.

blue color - holders that where all rusted and because that heat shield made noise while accelerating or braking.

brown color - strap that goes both around shield and catalytic converter (strap is a metal track full of holes) and i make it like a belt for jeans with screw (pink color).

its temoprary solution but it saves you 50 bucks at repair.

i hope it will help you


Modified by vocoder at 9:03 AM 6/27/2006

[vishesh]

i had the same problem. especialy when i am accelerating or braking.what i did?

i bought mufler straps at "Murrays Auto Parts" around $3-$4and i did as show on picture.

blue color - holders that where all rusted and because that heat shield made noise while accelerating or braking.

brown color - strap that goes both around shield and catalytic converter (strap is a metal track full of holes) and i make it like a belt for jeans with screw (pink color).

its temoprary solution but it saves you 50 bucks at repair.

i hope it will help you



Modified by vocoder at 9:03 AM 6/27/2006

But like Dominick said, it's not a heat shield, but rather a hole after the cat. The reason I thought I could do it myself is that maybe if I just replace the entire segment, from junction to the other (since it is one continuous piece, right?). Obviously, if welding was the only approach, there's no way I could/would do it myself. But if I remove/replace the entire section of pipe (including the cat) isn't it just a matter of a few bolts, a few new gaskets, lining up the flanges, and bolting it in place?

P.S., If that sounds really stupid, keep in mind, I don't know that much about cars...even less about exhaust systems.

[elan]

You wont be able to do this yourself unless you have a welder. And they were right, its not a heat shield but rather a hole probably right after the cat. I had the same thing with mine.

Best bet is to take it to a custom exhaust shop and either have them weld in a new pipe in that section, or get a whole new custom exhaust.

I think the tube size is either 2.25 or 2.5"

I think Dominick makes a point. Doing all those things yourself is not fun. I had the same issue. I took it to a shop and they replaced the converters with some aftermarket ones for about $220 including labour. He cut the old ones and welded the new ones. It took him about 40 minutes to complete. It's been about 2k5 miles and it's ok.
Modified by elan at 12:05 PM 6/28/2006

[elan]

You wont be able to do this yourself unless you have a welder. And they were right, its not a heat shield but rather a hole probably right after the cat. I had the same thing with mine.

Best bet is to take it to a custom exhaust shop and either have them weld in a new pipe in that section, or get a whole new custom exhaust.

I think the tube size is either 2.25 or 2.5"

I think Dominic makes a point. Doing all those things yourself is not fun. I had the same issue. I took it to a shop and they replaced the converters with some aftermarket ones for about $220 including labour. He cut the old ones and welded the new ones. It took him about 40 minutes to complete. It's been about 2k5 miles and it's ok.

[DominickJ30]

Best bet is to take it to a custom exhaust shop and either have them weld in a new pipe in that section, or get a whole new custom exhaust.

Quote »

A custom exhaust on the may cost you more than OEM. Get some quotes before you commit one way or another.

Check everythinginfiniti, I would say the whole exhaust piece by piece is around 4000 dollars from the dealer. Try to tell me the exhaust shop would be more expensive.

[brandonjustice93J30]

had the same growling noise a while ago and it was a hole...I think the shop charged like $80 to repair it....but it's rusted out again...so quick fix will be fairly inexpensive...but if you want to make sure it's gonna last a while have as much of the pipe replaced the first time and you wont have a headache like me in dealing with a second repair for the same problem