Why is it...

[bucko]

that some catalitic converters can work for hundreds of thousands of miles, and others will fail or plug? I just read a thread on here where a member has 197K on his truck, and the cats are plugged. I have 215K on my truck, and it's running fine. The cats on my truck appear to be original.

Does cold weather play a factor in condinsation/rust buildup in the exhaust, causing cats to clog? The cats are up front, so I'd think codensation would be minimal.

Is it the type of unleaded gas being used that can cause them to clog?

 

[RonD]

Mine is at 315k with original cats.

Yes, the exhaust has alot to do with how long exhaust pipe, cats and muffler will last.

When you burn gasoline(H) and oxygen(O) one of the by products is H2O(water), this is why exhaust systems have always rusted from the inside out, and why some use stainless steel pipes now.
But other factors like humid climate, more water vapor is sucked in, and less is evaporated on cool down, so water vapor condenses in low spots in exhaust system and starts the rusting.
And long term rich fuel/air mix also effects the exhaust system, not talking check engine light rich, just a little rich, maybe .5-1MPG rich.

 

[adsm08]

Running conditions, vehicle care, luck of the draw, they all play a part. Just like any other part on anything some individuals will last longer than others. If you have an injector or plug fail and start dumping raw fuel down the exhaust that will rip a cat up quick.

 

[Bronco638]

I used to work for Midas Corporate (the company that franchises, for the most part, all of the Midas Brake/Muffler shops). A lot of the guys that did exhaust design work were of the opinion that it took a good 15 minutes of highway driving to get the exhaust system hot enough to evaporate all of the moisture inside (obviously driving on local roads would take a little longer). If you drove short distances, the exhaust system never got warm enough to evaporate the moisture and the system would fail more quickly (rust out from the inside).

I wonder how much the environment has to do with it; Salt States versus Non-Salt States versus Humidity (FL) versus Dry (AZ). Etc., etc.

 

[adsm08]

Oh I am sure that those guys were correct, and that climate and humidity has a LOT to do with it.

I and my truck have lived in central PA our whole lives. My truck spent a large part of it's life doing runs of 20 minutes or less commuting either me or my dad to work. For a long time it was needed a new muffler every two years, like clock work. And I mean it was spot on, I could usually mark a day on a calendar that I would need a muffler and at least be in the right week.

Then I got a job 30 miles away and it lasted for quite some time.

 

[Dune Runner]

I'd have to agree with the short tripper being hard on CATs. Engine runs rich and never gets up to full temp. It's gotta be rough on em. I would imagine engine condition being a big factor too.