replacing cat convertors on 2006 lx (1 Viewer)

[Snowstorm]

How difficult is this? Anyone have any tips for what to look out for or things to know before attempting?

 

[JunkCrzr89]

If minimal rust, then it’s easy. If rusted all to hell, then it won’t be fun. Soak all the bolts and nuts in PB blaster for a while, or just cut the bolt heads/nuts with a cutoff wheel and angle grinder. Whatever you do, buy new OEM bolts, nuts, and gaskets.

 

[Snowstorm]

If minimal rust, then it’s easy. If rusted all to hell, then it won’t be fun. Soak all the bolts and nuts in PB blaster for a while, or just cut the bolt heads/nuts with a cutoff wheel and angle grinder. Whatever you do, buy new OEM bolts, nuts, and gaskets.

I was going to get one out and then pick up some stainless bolts and washers before doing the real job. I guess the oxygen sensors are in there, too, so I might replace them as long as I am in there.

I really hate muffler work of any kind, but when I look at what a shop wants I somehow find the strength to do it.

Right now there seems to be a shortage of cats to buy. I hope this is all a supply chain hangup and will clear itself out shortly.

 

[Trunk Monkey]

Curious why you're replacing (other than if yours got stolen). Really rare for cats to go bad, unless you ignored an o2 sensor forever and fouled the material.

 

[Snowstorm]

Curious why you're replacing (other than if yours got stolen). Really rare for cats to go bad, unless you ignored an o2 sensor forever and fouled the material.

I had this in the shop for something else and asked them to check the check engine light. The shop said the cats were bad and needed replacement.

I tried some cat cleaner and got no results. I am going to get a second opinion before going further. I can disconnect the battery and clear the CEL but as soon as the truck warms up it comes back.

I am also looking into removing them and cleaning them, which I am told can be done. But as long as I have them out I might as well replace them.

And speaking of rarely going out, my other LX has 335,000 on it and still runs like new. And there is no problem with the cats.

 

[FxFormat]

Try replacing O2 sensors first, also get yourself a scanner so you can see what code you are seeing. The shop probably want you to replace the cat so they can keep the old ones and sell, they're worth a fortune on the black market. Prius cats are going for like 7-800 each, it's crazy.

 

[yngmrostrvile]

You could quickly check the temp of the cats to see if bad. Outlet should be hotter than inlet. If inlet is same temp or hotter cat is bad.
Rare for cats to fail unless caused by other failure. Vacuum leak or exhaust leak before the cats.

 

[Biga27110]

Dont replace cats just need to replace O2 sensors

 

[suprarx7nut]

I had this in the shop for something else and asked them to check the check engine light. The shop said the cats were bad and needed replacement.

I tried some cat cleaner and got no results. I am going to get a second opinion before going further. I can disconnect the battery and clear the CEL but as soon as the truck warms up it comes back.

I am also looking into removing them and cleaning them, which I am told can be done. But as long as I have them out I might as well replace them.

And speaking of rarely going out, my other LX has 335,000 on it and still runs like new. And there is no problem with the cats.

If you or your mechanic has access to Techstream, there's a really neat test sequence in the software that shows you the O2 sensor response with purposefully enriched mixtures. It helps you verify if a sensor is weird or if the cat is truly damaged. Pretty surefire way to diagnose it without playing the parts swap game.

As others have said, the cats are rarely the problem in a healthy engine, but it does happen. My friend's GX (same @uz engine) had one factory cat go out. Forget the exact mileage, but it wasn't over 250k. He replaced the cheaper O2 sensors to no avail and then we tested it in Techstream. Verified the cat was indeed dead with the Techstream test and we then replaced it which corrected the problem.

 

[OEMGUY0720]

Let’s hypothetically say after getting the O2 sensors replaced doesn’t fix the CEL, then yes it could be the catalytic converter. But like what others have said here, Catalytic Converters don’t go bad ‘that easy’.
However a catalytic converter’s failure is commonly attributed to a coolant leak. So I would strongly suggest to check your heater Ts and rear coolant bypass and make sure they are leak-free.

 

[dealmaker]

I had this in the shop for something else and asked them to check the check engine light.

Honestly...you can buy get a scanner for cheap and look up your own codes. I wouldn't leave that solely to a mechanic to determine. I'm pretty much a 1- guy myself and even I do that. Haven't had to ferret one out on the LX, but I have ferreted out and replaced several O2 sensors on my 2UZ 4Runners.

 

[Snowstorm]

Honestly...you can buy get a scanner for cheap and look up your own codes. I wouldn't leave that solely to a mechanic to determine. I'm pretty much a 1- guy myself and even I do that. Haven't had to ferret one out on the LX, but I have ferreted out and replaced several O2 sensors on my 2UZ 4Runners.

I just picked up a fancy sort of scanner at Wally World that plugs into the scanner port and stays there. Then you download an app on you phone and through the wonders of bluetooth scan your codes.

I have a temp sensor I use to check the temp on the tires so it would be perfect to do the temp check on the cats.

The truck runs like new. I have been through the failed cat routine on a VW and a Chevy van so I know what this feels like. This runs too smooth for there to be a blockage.

But I will get after this and report back as to what I come up with.

And thanks to everyone. Hopefully others will get some use out of this thread.