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Exhaust Cali Smog /Rattling Cats

  • Thread starter Thread starter fredfifty
  • Start date Start date Jul 7, 2019

fredfifty

5 Year Member
Nov 23, 2011
318
57
59
SF Bay Area
Jul 7, 2019
#1
  • Jul 7, 2019
  • #1
my cali folks, will rattling cats (indicating the insides are breaking up) cause an automatic fail?
 
J

Jhp84

Active Member
Mar 2, 2019
100
11
28
california
Jul 8, 2019
#2
  • Jul 8, 2019
  • #2
Depends on the tech. Most likely will fail from the emissions coming out the tail pipe. CA standards are tough.
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,236
17,921
224
Massachusetts
Jul 8, 2019
#3
  • Jul 8, 2019
  • #3
Sure they aren't the heat shields?

But like said, if they rattle, it's likely you are betting bypass and higher emissions anyway.
 

Blown88GT

Founding Member
Nov 13, 1999
2,283
524
164
Palm Beach Gardens, FL
Jul 8, 2019
#4
  • Jul 8, 2019
  • #4
They had a recall on the cats for coming apart internally. Mine got replaced for free, then sold them when the hi-flow cats went in.
 

fredfifty

5 Year Member
Nov 23, 2011
318
57
59
SF Bay Area
Jul 9, 2019
#5
  • Jul 9, 2019
  • #5
Mustang5L5 said:
Sure they aren't the heat shields?

But like said, if they rattle, it's likely you are betting bypass and higher emissions anyway.
Click to expand...
it isnt the heat shields, i went under and checked. the sound is clearly inside the pipe on the driver side in between the rear and forward cats...so when the cats insides are rattling, is it going to be in the honeycomb itself? because i took the forward pipe off and nothing fell out, so im assuming the rattling object is in between the honeycomb in the cat?
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,236
17,921
224
Massachusetts
Jul 9, 2019
#6
  • Jul 9, 2019
  • #6
Could be broken on the other side.

The honeycomb is fused to the pipe itself, so when they start to break apart is when you get the noises. Where it breaks would determine where you see loose parts. Sometimes they stay intact but are loose in the pipe, and other times chunks fall out somewhere



This a stock 4-cat pipe? It's possible the broken area is in between the two cats where you can't see or anything can fall out
 

fredfifty

5 Year Member
Nov 23, 2011
318
57
59
SF Bay Area
Jul 10, 2019
#7
  • Jul 10, 2019
  • #7
Mustang5L5 said:
Could be broken on the other side.

The honeycomb is fused to the pipe itself, so when they start to break apart is when you get the noises. Where it breaks would determine where you see loose parts. Sometimes they stay intact but are loose in the pipe, and other times chunks fall out somewhere



This a stock 4-cat pipe? It's possible the broken area is in between the two cats where you can't see or anything can fall out
Click to expand...
it isnt between the cats because i was able to separate the x-pipe section from the driver side forward exhaust pipe that has the forward cat on it. It is a 3 piece component held together by band clamps. i was able to look at the honeycomb screen on both sides and on both pieces (x-pipe and forward pipe) and they were intact, not disturbed or broken. However, i do remember prior to the rattling (maybe a month) i did see small metal particles (small enough to fit thru the hioneycomb screen i think) on the ground that were obviously spat out the exhaust tailpipe. maybe that was the platinum?
 
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