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Never heard of a cat break in (cat burglar....?). Didn't when I replaced them in my last car, and honestly can't imagine GMC (every manufacturer?) does that with every new vehicle (new car = new cats).
Curious where you got that from.
 

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Curious where you got that from.
So is the cat.
1596166852269.png

Did the original poster follow procedure for breaking in the new cat? After replacement run at idle for 5 min, then 2500 rpm for 2 min, then turn engine off and let the engine and cat completely cool before driving. There is packing material around the honeycomb that must expand, then set. If not, exhaust gasses can bypass the converter material and the cat will not work properly.
Do you have a 'qualified' manufacturer's reference for that procedure to be shared with the forum?
 
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Catalytic Converter Break-In Periods
Brake & Front End



EMISSIONS / EXHAUST
Catalytic Converter Break-In Periods

By
Brake and Front End Staff
on
May 21, 2014
A replacement catalytic converter needs a proper “break-in” period. If the converter is not warmed-up (broken-in) properly, the substrate inside could be adversely affected and eventually cause the converter to fail down the road.

The problem typically occurs when a shop installs the converter and immediately returns the vehicle to the customer. The customer drives away and runs the car for a long distance or lets the vehicle idle for an extended period of time. Under these conditions, the matting, which is intended to secure the substrate, will not expand properly and hold it in place.

Converter matting is made from a mineral called vermiculite, which is held together by a fiber mat and a binder. This matting is wrapped around the converter’s ceramic brick. The matting is installed in the converter in an unexpanded state. During the first heat up, the fiber mat and binder burn off and the matting actually gets looser before it expands to fill the converter cavity to hold the ceramic brick in place. If that warm up is not done properly, the brick can come loose and get damaged. That rattle you might hear inside the converter shell is a sure telltale for this problem.

The best way to avoid this service issue and potential warranty problems is to include the warm-up period as a key part of your overall converter installation procedure. This heating cycle will allow for correct matting expansion.

Here are suggested steps for a proper break-in or warm-up:
• Start the vehicle, but do not rev the engine;
• Idle the vehicle and allow it to warm up slowly;
• After 5 minutes, increase the engine speed to 2500 rpm;
• Hold at 2500 rpm for 2 minutes; and
• Allow vehicle to cool down.

Courtesy of Eastern Catalytic
For additional information, call your distributor or visit: www.easterncatalytic.com.
 

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I have replaced several cats on a variety of cars, including my 2009 Acadia.

One way to check the proper operation of the cat is with a laser thermometer. The cat should be significantly hotter than the exhaust manifold. If there is no difference in temperature, the catalyst is not burning hydrocarbons from the exhaust and you have a dead kitty.
 

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Never heard of a cat break in (cat burglar....?). Didn't when I replaced them in my last car, and honestly can't imagine GMC (every manufacturer?) does that with every new vehicle (new car = new cats).
Curious where you got that from.
+1, Have replaced cats on several vehicles, never did any sort of break in, never had an issue, but I suppose anything is possible.
 

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The break-in instructions may be for the less expensive aftermarket cats, in this case Eastern Catalytic. One would assume that the OEM cats are manufactured in a different way, using more platinum and different matting, for instance so they may have different break-in procedures, or none at all. These products also tend to be much more expensive, so they may not be the first choice for DIYers of 10+ year old vehicles.

For instance, Walker states there is no break-in period for their aftermarket cats.

The point is, some aftermarket manufacturers specify a break-in procedure. If that is not followed, there may be performance issues with their products. If the original poster had such a cat and did not follow the break-in procedure, he may not get optimal performance from that particular part.

Everybody else's individual experience may be different, and the failure rate may be low if break-in is not followed, but if break-in was specified for that particular product and break-in was not followed, it may be the reason for sub-par performance.
 

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Anything other than from the maker of a product should be considered unacceptable as a 'qualified' reference. Blog posts and parts seller's pages don't fit the bill.
 

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Eastern's product reminds me of those pressed sponges that expand when wet - not a product I would consider spending $$ on to repair my vehicle.
 

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Eastern's product reminds me of those pressed sponges that expand when wet - not a product I would consider spending $$ on to repair my vehicle.
Well, the difference in price being $180 or so vs about triple that for OEM is significant. I just replaced mine with an Eastern Cat, and the rear O2 output on that bank is back up to par. My Acadia has 220k miles on it. Right now, I drive it less than 100 miles per week. I will sell the car long before the 50k warranty on the Cat is up.

I have purchased many AC Delco replacement parts, and many less expensive aftermarket parts. A big factor for me is how long do I need the repair to last, and how big of a Pain is it to replace the part? I used an AC Delco Front Evap Core because I never, ever want to do that job again since it took multiple days to complete. If need be, I can find two hours to replace another cat in a few years.
 

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Well, the difference in price being $180 or so vs about triple that for OEM is significant. ...
That's your choice. Whenever you post a procedure like you did, make sure you provide an explanation that it applies to a specific manufacturer's part. It's misleading to imply such a procedure should be followed by everyone.
 

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The Info I posted is the same as the .pdf from the Eastern Cat site. It just happened to have been posted by whoever Brake and Front End Stuff is. There is a link to the same info at the bottom of the post, which refers to the manufacturer's site. The same recommendation was used by the manufacturer of another cat that I recently replaced on a 2008 Saturn Aura 4 cylinder. The exhaust manifold and Cat were one piece. That job was more intense than the Acadia.
 

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I'm almost thinking Eastern Cats (are they well known? reputable? honest question) states this is "an out".
"I need to return these, they are faulty"
"Can you please provide documented proof that you broke them in per the procedure provided? No, didn't think so"
Can you post the other brand who states the same?
Any of the auto manufacturers do that break-in? I'd say an absolute no. Wouldn't be possible.
I replaced the cats on my Z06 with Magnaflow universal units. No mention of break-in requirements. Never had an issue, 4 years of daily driving (except winter) with them in place.
 

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I now that. Many people won't be buying Eastern cats. A lot of folks prefer Western ones. LOL
 

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I think that it is fair to say, whatever brand of Cat you purchase, read and follow the instructions. For some, slapping it in and driving away is fine. For others, especially the lower cost cats, perhaps not.
 

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I think that it is fair to say, whatever brand of Cat you purchase, read and follow the instructions. For some, slapping it in and driving away is fine. For others, especially the lower cost cats, perhaps not.
I have yet to see a catalytic converter come with an instruction sheet attached to it. Unfortunately, it's also against some people's principles to 'read and follow' manufacturer's installation instructions. Keep on cheapin' on, man! LOL
 

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Discussion Starter #57
Sorry for late response i was busy beating up myself and getting an earful from my wife for wasting money on cheap parts online. Its beginning to look like both CATs are defective. Good thing is a can get my money back, bad news is i have to find replacement right away because i have a new problem now. The engine runs hot and gets the temp 2 notches up and doesnt go down unless i am just cruising along, as soon as i go up a hill or just have to step on the gas it goes up again but never pass 3 notches. Is this a direct consequence of driving with 2 crappy replacement CATs ?
 

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Sorry for late response i was busy beating up myself and getting an earful from my wife for wasting money on cheap parts online. Its beginning to look like both CATs are defective. Good thing is a can get my money back, bad news is i have to find replacement right away because i have a new problem now. The engine runs hot and gets the temp 2 notches up and doesnt go down unless i am just cruising along, as soon as i go up a hill or just have to step on the gas it goes up again but never pass 3 notches. Is this a direct consequence of driving with 2 crappy replacement CATs ?
Sounds like a potential thermostat issue opening too soon, which can cause incorrect combustion temperatures, which could be the cause of your cats going in the first place.
It’s probably time to take your car to be looked at by a professional.


Sent from my iPhone using Tapatalk
 

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Sounds like a potential thermostat issue opening too soon, which can cause incorrect combustion temperatures, which could be the cause of your cats going in the first place.
Also possible the radiator is low on coolant. Many folks don't check coolant level at the radiator. They rely on the expansion reservoir marks.
 
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