Well, shoot... then you have to start asking yourself, why did the substrate come apart inside the cat? There really are no good answers there.

 

I don't know what could've caused it. I don't remember hitting any bad potholes on recent weeks. This really makes RFHC tempting.

 

I was thinking more along the lines of your car running rich for too long, or misfiring for a length of time before a coil-pack miraculously started working again. Basically, burning a chunk of substrate that ended up rattling inside. Then again, there's no mistaking a mis-fire situation on a 6-cylinder engine, so if that's been happening, you surely would have known it, and there would be codes recorded for the event.

I'm no mechanic, but that's my thinking. See what other kind of input you can get as to why a 3-4 year old catalytic converter would start rattling.

Yes, but resonated... that means Fast Intentions and an 8-week wait, because they build to order.

 

Which is precisely why I replace parts before they're even remotely close to needing it... LOL

Sorry. Just muddying the waters...

Rochester makes an excellent point...that's too early. We can probably all relate many instances where cats were good for 100K miles or more. There must have been an issue, code or indication why the guts are destructing. Shields, yes, internals? Hmmm...

Sean

 

I might just check it out for myself when I get my car up on a lift for an oil change. I'm not sure if they actually tried to clamp down the heat shield and decided to jump to conclusions by saying the cat is bad. The car still drives fine, I've had zero issues, even on my 9+hr drives from NC to NJ.

 

I would definitely check it out. A 'bad' cat with no CEL? Interesting. Dealership might have just wanted an extra buck or two and went 'full monty'.

Sean

 

Do I need to reset the ecu after the install of my new y pipe ?

 

Luckily, it's covered under warranty

 

Not neccesary.

 

Yup, I couldn't agree more. Definitely one of my top mods and money well spent. Makes me just enjoy driving the car that much more.... unlike your experience with the Q50 loaner car. LOL

 

Nice to see your dealer covered this under warranty. I believe since it is an emissions related item that Infiniti actually extends the warranty by another year (5 years instead of 4).


Bad CAT's are not all that uncommon. I've run across it many times. Most common cause is that the matting inside the CAT fails to expand properly when the car/CAT is new and therefor never properly holds the ceramic brick in place. Eventually the brick will start to move around and then begin to rattle.

 

So what you're saying is that the substrate becomes dislodged from the walls of the cat, and it's the entire "brick" that's rattling?

 

Ugh yea that loaner is just poor man's Q50a I guess... At least the VQ37 wasn't taken away as part of the base model cuts. LOL
Leatherette seats, no heated seats, no nav, no power mirror, idk what else it's missing since I'm not very well aware of what other Q50's have with better packages.

 

Also speaking of dealerships covering stuff under warranty, they found the water leak on the passenger side making the carpet wet caused by a clogged sunroof drain and also replaced or are still replacing my rear subframe bushing which has been leaking for a while now all under warranty as well, hence maybe why they still haven't called me today with an update, probably keeping it till tomorrow if they got the part late today. Can't wait to get back in my sedan finally...

 

It's the matting that surrounds the substrate that can cause the substrate to come loose. This matting is designed to expand and in-turn hold the ceramic substrate in place, but if it doesn't expand properly or doesn't properly seat itself it is possible for it to come loose from the housing allowing the entire piece of ceramic substrate to rattle inside the housing. I've had this happen on two previous cars and have seen it happen on several others. Here's a quick cross-sectional view of what I'm referring to.