I have searched and searched and this is what I am trying to understand. I am about to turn over 200k on my 03 Silverado and I am doing some maintenance. I have seen where some say the cats last as long as the vehicle but then say the life expectancy is 100k....not sure what kind of vehicle they are expecting to only get that out of now. So my question is should I replace my cats or do they not wear out?

 

If it aint broke dont fix it. I wouldn't personally but than again i dont have any.

 

Cats have no set life expectancy because there are too many variables(temp, fuel, average speed, tuneing etc etc) and for the most part only get replaced when they clogg up or break up internally. That being said if you're the guy with money in the bank and no plans to sell your truck or switch to long tube headers I could see buying a new set to have handy before GM stops making them.

I have seen cats clog at 30k miles because of a poor design and I've seen plenty of cars with over 200k and no cat problems. Luck of the draw some times.

 

Cats have to last 8 years(maybe 160,000 miles not sure on the mileage) under the emissions warranty part of a new truck. So if they fail under 8 years, GM must replace them under warranty, which is longer than yor standard powertrain warranty. The feds make GM runs cats, but they also make GM used good enough cats to last that long.
Cheaper cats have less precious metals which do the catalyzing, that's part of the reason new stock and new highend cats cost more.

I bought cheap cats and after 2 years they were done. If your ECM/PCM tune has the aftercat O2 sensor monitoring still enabled, then so long as you don't get a code for cat insufficiency, you are golden.

peace
Hog

 

Agreed^^

I have seen less than 100,000 mile cats get clogged up and bad to where they could restrict alot of power! This was on a cousins truck btw.

 

Yea I have a rear 02 sensor throwing a code right now but it says the sensor is not functioning so tomorrow I am going to replace that one and see if it is the cat after all. I have had this truck for a long time and plan to keep it and definitely do not plan on LT's for the truck as it is my quieter vehicle and its my tow vehicle. Once I replace the sensor I guess that will be the definite answer. I appreciate the replies guys.

 

I find they work best on a shelf.

 

The OE technical design life for the cats under optimum circumstances and max emission reduction is 100,000 miles or 8 years. After 100K they began to slowly loose efficiency until they start setting cat failure codes. It really is the luck of the draw and there are a ton of factors.

Anything over 100,000 and life depends on use how you drive where you drive if you are a lead footed driver or easy driver or if you live somewhere in the mountains where a truck may spend a ton of time under WOT pulling heavy grades or or heavy loads for that matter.

As stated earlier if you are really planning on keeping the truck another 100K or 5 years I would order a GM set while you still can. 5 years ago I put a ypipe on my 98 bigblock and the front section was 575. Last week I had a customer come in and my cost on the front section that has one cat only is 1600 and the rear cat/muffler section is discontinued and there is not a NOS one to be found for any amount of money. Aftermarket cats are ok but GM are waaay better long term quality and cleaning performance when they are in a bone stock OE non screwed with application.

 

This is what I have been looking for. I still have not had a chance to change my 02 sensor because of all the rain we are having here in south GA. I do plan on keeping this truck a while so I am going to look into a new set of GM cats. Thanks for the advice!

 

People in Cali dont think the same. Otherwise yup they do! If you keep them you could always sell them to people who really do need them. Those OEM cats sure do cost some good $.