03 Pathfinder - Passenger side resonator rattle

[amaff]

I've got an 03 Pathfinder that after a total of about 20 hours driving this weekend (from ATL to Orlando and back, with some in-city driving in Orlando) had developed what sounded a lot like a death rattle.

After some searching it looked like it was more than likely just the exhuast heat shield. After getting the car up on ramps tonight, it sounded internal to the exhaust but I pulled the heat shield to be sure. Sure enough, even after removing the heat shield, the passenger side 2nd cat is still rattling.

2 questions:
1 - Is that a Cat or a Muffler? The FSM doesn't specify.
2 - If it's a cat: it doesn't look like it's monitored by an O2 sensor. Any reason I shouldn't just pull it and hog that thing out?
3 - If it's a muffler: Any reason I shouldn't just pull it and hog that thing out? LOL

Thanks in advance

~Andrew

[Pwnin O'Brien]

What you're probably talking about is the resonator (does it look like the part picture in this thread: Resonator thread). If you removed all of the heat shields from the down pipe then you might have a rusty resonator which has fallen apart on the inside. The resonator is not required and not related to emissions so you can safely remove it if you want, it will make your vehicle noticeably louder.

[amaff]

Heh, that's funny because all the parts depots have those listed as cats (which are expensive) instead of resonators (which are pretty cheap by comparison). The noise is definitely internal, as opposed to the link which was a crack in the resonator itself. I think step 1 is going to be to try and just clear it out to get rid of the rattle. If that doesn't work, I'll just weld another resonator in. I'm HOPING that whatever it is that fell apart in there will just fall out as soon as I get it off the truck.

Hell, a little extra noise never hurt anyone

Thanks again

[amaff]

Well, we were both right.
It is most definitely a resonator.

And the cat was most definitely the cause of the rattle.
Once I got the mid-pipe out of the way and flipped it to help get it out from between the crossmember and the body, this dropped out:


I took it out of the garage to prevent further mess then up-ended it:


And the other pic of the damage:


I need the truck to go to work tomorrow, so I didn't have time to drop the cat out to actually gut it, but I did take the time to fab up the ol' spark-plug non fouler trick (I <3 my drill press ), so at a minimum it should clear up the CEL. It also explains the CEL. I'm an old Mazda Protege guy (used to have an 03 Protege5) and after installing an aftermarket header that would delete the pre-cat, the spark-plug non fouler was a pretty common trick . And if I ever hear that rattle again, I'll know what to do to fix it. And if it ever happens again, i'm taking a long screw-driver and a hammer to the rest of the catalyst

Thanks for the help

I have to say, this is one of the more informative forums that I've been on (and I'm actively on a number of automotive forums through my various interests )

[fueler]

I wonder why it failed. Props on gutting it. Let us know if you feel a performance gain.

[amaff]

I wonder why it failed. Props on gutting it. Let us know if you feel a performance gain.

No idea. The truck's got 135K on it so it could be anything from 'old age' to too much fuel hitting it for too long from the plugs I pulled out last week that likely had all 135K on them. A couple of the gaps were in the .050s, 1 was a .065, 1 was .070, and 2 were in the .080 range, so it was bad

RE: gutting it: I didn't. It 1/2 gutted itself. I didn't have time to pull it and do it properly this time around unfortunately
RE: Performance gain: probably not much, besides the performance I picked BACK up from having a choked up exhaust pipe...

[fueler]

yeah, here at my work we have a chevy van with 170k miles that also had a clogged cat and was running terrible. It wouldn't go up hills and had a check engine light. We gutted the cat, and now it has power again & check engine light is gone!!

[amaff]

Looks like clearing the resonator of debris and plopping the spark-plug non-fouler onto the O2 sensor did the trick. I cleared the codes with an OBDII scanner and have driven around for a few days. Plugged the scanner back in and the Catalyst and both O2 sensor banks came back Ready. Thanks ya'll

~Andrew

[Tunerguy1989]

Hey quick question this may sound dumb but someone told me that the 01 pathfinder 4x4 has four catylic converters does that sound right? I have never heard of a car having more than two, But I haven't gotten underneath my pathy in a while and last time I did I didn't even look so I'm just wondering.

[Empty V]

It only has two but more often then not people think the resonators are cats.