Undercarraige Rust Issue

[FireGuy85]

Hi everyone,

I registered here on the site when I bought my 2004 G35X around xmas of 2010, but never really had an issue until recently. Hoping to get some advice from you all.

Around the middle of December, I noticed I was getting about 10-12 miles per gallon, down from about 18-20. Had the dealership do an oil change and they did their normal "inspection" but they didn't mention anything. Still having the issue, now accompanied by a strange noise (which I'll start a different post for). I decided to jack the car up to see if I could notice anything/see any leaks. As soon as I got underneath, I found what seems to be a major rust issue. I've tried going through the FSMs for a picture of this part, but cannot locate one. I think it is an insulator or maybe heat shield, but can't tell.

If anyone knows what this is, and if it is major, I'd really appreciate it. Thanks all!

http://s1153.photobucket.com/albums/p51 ... 1199_o.jpg

http://s1153.photobucket.com/albums/p51 ... 3063_o.jpg

[HighTech]

That is definitiely a heat shield. The worm clamps are a decent short term fix but nothing last forever in the rust belt.

[telcoman]

Hi everyone,

I registered here on the site when I bought my 2004 G35X around xmas of 2010, but never really had an issue until recently. Hoping to get some advice from you all.

Around the middle of December, I noticed I was getting about 10-12 miles per gallon, down from about 18-20. Had the dealership do an oil change and they did their normal "inspection" but they didn't mention anything. Still having the issue, now accompanied by a strange noise (which I'll start a different post for). I decided to jack the car up to see if I could notice anything/see any leaks. As soon as I got underneath, I found what seems to be a major rust issue. I've tried going through the FSMs for a picture of this part, but cannot locate one. I think it is an insulator or maybe heat shield, but can't tell.

If anyone knows what this is, and if it is major, I'd really appreciate it. Thanks all!

http://s1153.photobucket.com/albums/p51 ... 1199_o.jpg

http://s1153.photobucket.com/albums/p51 ... 3063_o.jpg

Looks like a catalytic converter to me

http://www.bing.com/shopping/search?q=c ... &FORM=HURE

Telcoman

[FireGuy85]

That is definitiely a heat shield. The worm clamps are a decent short term fix but nothing last forever in the rust belt.

That's what I was thinking, thanks. I have read about people removing them completely- is this the only option, or can they be replaced? Also, could this be the cause of any noises during acceleration?

[HighTech]

I have removed them before, but considering that you have the AWD model, and it looks like that shield is pretty close to your transmission/transfer case pan, I would want it on there. I took one off of my 240sx and my floor would get pretty warm after a long drive. Up to you, just make sure the transmission isn't taking too much extra heat.

A weakened and therefore loose heatshield will usually produce a raspy/rattling noise during acceleration. As far as the catalytic converter is concerned, it is common for them to get a little rusty. They deal with some pretty extreme temperatures, replacing one can be easy with the correct tools. I'm from Ohio and they salt the roads when it snows. In my experience you need to forget about trying to unbolt the attachment hardware, torch off the old stuff and replace it with new. Heat is your friend with this job, too much prying/hammering will have you screwing up the flanges.

[FireGuy85]

I have removed them before, but considering that you have the AWD model, and it looks like that shield is pretty close to your transmission/transfer case pan, I would want it on there. I took one off of my 240sx and my floor would get pretty warm after a long drive. Up to you, just make sure the transmission isn't taking too much extra heat.

Thanks again. I did so more searching, and came across this, which mimics the sound. Right at 0:02-0:06 is basically the same noise I am having, and during the same time (acceleration). Can you tell if this is the result of the heat shield?
http://www.youtube.com/watch?v=6ut_Vf_sIBo

[RED_DET]

It is the heatshield for the cats and appears someone has put clamps around them to hold them into place. Before wasting a lot of time trying to source those shields, just buy some exhaust wrap and call it a day if you are concerned about the heat.

[HighTech]

Its a little hard to tell watching it from my phone. But i think i heard it, it will be a rattling/raspy noise that will come and go. My nissan used to produce the noise at 2700rpm. I'm with RED_DET on the solution, remove the decaying shield and replace it with some good heat wrap. If the noise is gone afterwards you know for sure you've found the culprit.

DEI makes some good stuff for this kind of thing, the heatshield alone would probably be hard to find and will require utilizing the factory mounting bolts on the converter, which are fused to the coverter with rust at this point.