Topic: The General bought me some new Cat's today.

[BNASTY]

Today I went into my favorite dealership to get the routine oil change and once over.   Modern Auto, Washington MO.

I ask my service rep to check on a "metallic" rattling sound under the truck near the O2 sensors while he had it in the shop and on the rack.

I went to lunch, Subway $5 footlong, and returned to the dealership to find out they are replacing both Catalytic converters on GM's dime. 
( 8 year something or other )

Yeah me, Soooo after another half hour wait I roll out with a fresh new Cat system and head over to the local muffler shop.

I have been wanting a little louder exhaust system than the aftermarket Gibson stuff that came with the truck so I dumped the 25" long
Gibson muffler for a 14" High performance Magnaflow.

The sound is not over bearing and not noticeably louder in the cab, but outside when you get on it that's when you hear the difference. 

Installation, Muffler, Tax was only $150.

Dealership estimate - Warranty replacement Cat system + labor $ 1,013.98
Lube, Oil, Filter, 32 point check??  $28.00
Magnaflow, Installation, Tax $150

The Nastymobile is ready for a trip to KC for fire & ice if I can get the wife on board.

B

[oHIobellboy]

Sounds like that dealer is gonna take good care of you so you keep coming back

[MoAv]

That's really great B!! Can't wait to hear the new sound...

( umm, before the train horns... )   

[MyBigToy]

Mine were replaced over a year ago with less than 50K on the clock. It's a pretty common problem with the trucks. They simply replace the whole y-pipe/cat assembly so it's not a big job. Needless to say, I'd never use the stock system on my dime since you can get it done a lot cheaper elsewhere.

[Main One]

I had mine replaced at close to 80,000 miles under warranty.  Emissions equipment is covered by federal law for at least 80,000 miles on things new enough to be Avalanches.  Had to replace another one at around 125,000 miles.  Got it done at a local muffler shop for much less.  As MBT says, they replace both cats and the y-pipe assembly at the dealer, largely I think because the dealers don't have to have welders.  At the muffler shop, they cut out the bad cat and welded in a replacement for I believe under $200.

[BNASTY]

Well,

It appears my original rattling noise is still there.  My first guess was the O2 sensors but they didn't agree.

I can officially rule out Muffler and Catalytic converters so I'm gonna take it back for a closer look next week, I may
have to Physically show them this time. 

B

[mEYEscndfvrtluv]

The Nastymobile is ready for a trip to KC for fire & ice if I can get the wife on board.

B

SWEET!

[BNASTY]

My original diagnosis was correct.

It was in fact the O2 Sensor.  The Post Cat driver side to be exact.

Replaced, no more stupid rattle.  I am Sooooo happy.

I will need to break the old O2 sensor down to find out why it was
making so much noise and not throwing any faults.

B 

[Donnie1]

Good to see you on here B. glad you got it fixed.

[BNASTY]

I have been busy fighting with my new job and having fun taking Josh to wrestling practice and tournaments.

Josh took 2nd two weeks ago at the youth USA districts, and 4th last weekend at regionals to qualify for the USA state tournament.  Two weeks from now we are going to Mizzou for his final tournament of the season.

Its gonna be fun and we are proud of everything he has done this year.

I'll be back on the site more when things settle down a little.

B