Bad Catalytic Converter

I have a 2008 Toyota Tundra 5.7. It's got about 170,000 miles and it started making a rattling noise that was coming from the passenger side cat. I'm curious if this is the normal lifespan of this particular model of catalytic converters or if I need to inspect something else on my truck. It eventually threw a code, P0420. I am located in California, so looking for an approved cat is pricey. Any pro tips to help me pass smog? Thanks!

 

Lifespan: Hard to say, it seems like there's no rhyme or reason for when they go out. My '08 is approach 300k on the OE CATs, and I have no issues (that I know of )

Rattling noise and P0420 is pretty indicative of a failed CAT, but that is not absolute. The P0420 code could also be from a 'bank 1' o2 sensor or even an exhaust leak (which could be source of the rattle). o2 sensors are definitely a more common fail and would definitely be a cheaper solution if that was the source of the code...

Here's a video I found doing a quick search on the interwebs that will give you an idea of where else to look, and some troubleshooting advice:

https://youtu.be/-50S07UXiRk

I will say that if you do find yourself needing to replace a CAT, just know that our rigs DO NOT seem to like aftermarket CATs for some reason. When CAT theft was out of control a few years ago, many Tundra owners opted to try aftermarket options instead of waiting months for OE CATs to show up, but they were met w/compatibility problems that led to frequent error codes, etc...

Good luck on a quick and relatively painless resolution!!

 

Give the tailpipe a sniff, an O2 sensor won't stink like sulfur. Wiggle the pipe to check if your rattle is a loose hanger. Definitely sounds like bad cat symptoms. I was able to make a magnaflow cat work, after throwing several codes several times and just kept clearing it and sending it.

 

My buddy has replaced his passenger side cat on his 2008 twice. He used aftermarket the first time and it lasted until just after the warranty expired. The second replacement was a factory unit that he bought discounted. It has been on for about four months. Bill

 

Lost the driver's side cat at similar mileage on 07. Codes then the rattle as it blew out I presume.

Replaced with Welker bolt in. So far so good. Found on Amazon. It wasn’t the cheapest but had decent reviews.

I did call around and found muffler shops that would weld in a generic cat claiming they worked well. Quotes were around $500 for cat & install.

 

My 2008 started to rattle on the driver's side about 260,000. But, it was shortly after I dropped off a road and banged against the frame. I put a Walker on it from Rockauto. I have had good luck with Walkers in the past. It lasted about 30,000 miles before it started rattling again. Catalyst broke loose from the metal. I then replaced it with an OEM one. I am guessing that the Walker on got banged around during shipping, but that is just a guess. When I bought the OEM one they would not ship it. I had to pick it up.

 

I replaced the driver side cat on my 2008 5.7 at about 180k. I used a Walker bolt on. It fit perfectly, cost about 1/8th price of an OEM cat and worked without a problem for about three years and 40k or so miles before I sold the truck. It was so cheap and so easy to replace I really wouldn't have cared if I had to replace it every 40k or 50k miles. Never had a code or check engine light.