When V8 Cats go bad?

[TeryT]

I've got about 190k miles on my V8 and on a recent trip the dash CEL lights came on and it was the infamous PO 420-430 codes. I've read threads on here about how replacing the downstream O2 sensors and using the spacers has cured the problem for many. I'll likely do the same thing as the CEL lights annoy me (yes, I've reset the CELs twice, but they pop back on after 20 miles or so).

From my understanding the 4th gen V8s (perhaps V6s too) have three cats. I had a cat replaced under the recall at around 85k, and I'm not 100% sure, but I'm thinking it was the big main cat the two banks feed into. (did anyone else have their's replaced under the recall and is my thinking correct in this?)

Again, I plan on replacing the two downstream O2 sensors (with spacers). But my question is this - What mileage are others getting before their cats actually go completely south?

 

[WhiteBoomer04]

My 04 V8 4x4 has 230,000 and still no cat problems

My sons 04 V6 2x4 with 280,000 just started the 430 code a few months back.

I'm in CA so have to decide what to do. They do a visual check on the sensors! So far Cataclean has not worked. Neither has replacing the gas cap lol.

 

[Jeffy]

I'm in CA so have to decide what to do. They do a visual check on the sensors! So far Cataclean has not worked. Neither has replacing the gas cap lol.

CA changed it, they only do a visual of the engine bay and scan the OBDII. They haven't looked underneath for either of the last 2 smogs I did.

My '03 v8 had 200k with no codes.

 

[WhiteBoomer04]

CA changed it, they only do a visual of the engine bay and scan the OBDII. They haven't looked underneath for either of the last 2 smogs I did.

My '03 v8 had 200k with no codes.

My 04 comes up for smog in April 19. They inspected my o2's last time i was in.out:

 

[TeryT]

My 04 V8 4x4 has 230,000 and still no cat problems

My sons 04 V6 2x4 with 280,000 just started the 430 code a few months back.

I'm in CA so have to decide what to do. They do a visual check on the sensors! So far Cataclean has not worked. Neither has replacing the gas cap lol.

Thanks, so there's a good chance it's not my cats, but rather the sensors!

It doesn't surprise me that California visually inspects! Here in AZ they don't look at anything except the computer readout. I think I will try the sensor replacement first, and only go the spacer route if I have to. And as others have pointed out, it's not that "bad" cats won't pass smog, it's usually just that they have dropped a couple percent in efficiency and the sensors (if good) don't like it!

 

[TeryT]

V8s for sale hard to find!

BTW - Part of the discussion with my wife was regarding if it needed new cats and we had to fork out a few grand. She was asking if we wanted to put that kind of money into a 15 year old vehicle, which is certainly a fair question! We tow a 25' travel trailer with it, so we definitely need the V8.

I did a little search and found out that V8 4Runners for sale are pretty hard to find! Seems people are definitely hanging on to them much more than the V6s. I only found a couple V8s anywhere and they both had nearly 200k on them, which (of course) wouldn't make any sense . . .

Ours is still in remarkably good shape and drives almost like new (seriously). So my answer to her was basically, "Yes, even if we have to buy new cats, we need to keep it."

 

[WhiteBoomer04]

CA changed it, they only do a visual of the engine bay and scan the OBDII.

Have you seen anything in wriitng to this effect?

I see reference to a visual inspection of the exhaust system at every link I look at. Here's an example, if you scroll down a bit...

https://www.emissions.org/loc/california-emissions-testing/

Quoting... "The physical inspection will look at whether your vehicle and its exhaust system, work to limit emissions."

 

[Jeffy]

BTW - Part of the discussion with my wife was regarding if it needed new cats and we had to fork out a few grand.

That's an awfully steep price...Universal cats are only about 100 bucks and shouldn't take more than an hour or two to weld in. How did the price get so high?

Have you seen anything in wriitng to this effect?

I see reference to a visual inspection of the exhaust system at every link I look at. Here's an example, if you scroll down a bit...

https://www.emissions.org/loc/california-emissions-testing/

Quoting... "The physical inspection will look at whether your vehicle and its exhaust system, work to limit emissions."

I can't remember where I got that info, but someone had a link stating the new visual inspection didn't look at anything further downstream than the headers. I just assumed that was true since my last two smogs they didn't check the exhaust.

 

[Tanker Yanker]

Thanks, so there's a good chance it's not my cats, but rather the sensors!

TeryT, it's definitely the cats that are bad....the front pair mated to the exhaust manifolds. 02 sensors are fine, just install the spacers if nobody will be doing a visual emissions inspection. I installed the 02 simulator to clear mine up instead of spacers. New cats are the only real way to actually "fix" the truck though.

PM me if you need any help.

 

[TeryT]

That's an awfully steep price...Universal cats are only about 100 bucks and shouldn't take more than an hour or two to weld in. How did the price get so high?

Well I did stop by my favorite Toyota dealer and talked to my main man there. He agreed that the codes could be just the sensors, and said if it did wind-up needing cats I would be better off going to a muffler shop. He didn't tell me the dealer price, but he told me how much someone saved going to a muffler shop and that told me the $2000 figure wasn't too far off - at least as far as the dealer is concerned.

(By the way, this is the kind of relationship I wish everyone could have with their local dealer service dept. These guys have done right by me over the past dozen years on numerous occasions, and have actually been quite competitive with the local independent AAA shop! That's what keeps me going back.)

So I got the local O'Reiley's to price match Amazon on a pair of Denzo downstream O2 sensors for $104, and they will rent me the sensor removal tool for free So looking like a little Saturday afternoon project!

 

[0verland]

Well I did stop by my favorite Toyota dealer and talked to my main man there. He agreed that the codes could be just the sensors, and said if it did wind-up needing cats I would be better off going to a muffler shop. He didn't tell me the dealer price, but he told me how much someone saved going to a muffler shop and that told me the $2000 figure wasn't too far off - at least as far as the dealer is concerned.

(By the way, this is the kind of relationship I wish everyone could have with their local dealer service dept. These guys have done right by me over the past dozen years on numerous occasions, and have actually been quite competitive with the local independent AAA shop! That's what keeps me going back.)

So I got the local O'Reiley's to price match Amazon on a pair of Denzo downstream O2 sensors for $104, and they will rent me the sensor removal tool for free So looking like a little Saturday afternoon project!

Tery,

It could possibly be the sensors but I am betting its the cats. You can get a set of simple universal cats from FlowMaster, Magnaflow, etc and just have the old ones cut out and new welded in for pretty inexpensive. The cats are like $100-$120~ and the labor is about an hours labor.

If you end up going that route I highly suggest getting in touch with Chris at Scottsdale Muffler. He's the owner and a great guy to work with. Extremely reasonable pricing and he will probably even sell your old cats he his precious metal guy, that way you can get some money back against the new cats.

Any how he's done the exhausts on the last 7 of my cars/trucks with amazing workmanship. If you have any questions or need more info feel free to PM me.

 

[rwh963]

are the replacement catalytics sold through toyota dealer of equal quality to the original assembly line parts? the new cat warranties are about 10 yr/150k miles. the originals last a long time, but wondering if the replacements are of the same quality.

 

[Jeffy]

are the replacement catalytics sold through toyota dealer of equal quality to the original assembly line parts? the new car warranties are about 10 yr/150k miles.
the originals last a long time, but wondering if the replacements are of the same quality.

If you buy replacement parts from the Toyota dealership, they'll be the same parts that were installed from factory

 

[TeryT]

Tery,

It could possibly be the sensors but I am betting its the cats. You can get a set of simple universal cats from FlowMaster, Magnaflow, etc and just have the old ones cut out and new welded in for pretty inexpensive. The cats are like $100-$120~ and the labor is about an hours labor.

If you end up going that route I highly suggest getting in touch with Chris at Scottsdale Muffler. He's the owner and a great guy to work with. Extremely reasonable pricing and he will probably even sell your old cats he his precious metal guy, that way you can get some money back against the new cats.

Any how he's done the exhausts on the last 7 of my cars/trucks with amazing workmanship. If you have any questions or need more info feel free to PM me.

Thanks! I just might connect with Chris!

I found the Toyota Service Bulletin I had the replacement cat done under back in 2007 at around 75k miles. It replaced the "Exhaust front pipe assembly" which has the large cat the left & right banks feed into, just ahead of the muffler. This was a "secret" bulletin for people who complained of a strong sulfur smell (it didn't really help much at all).

So that means the left & right bank cats are the originals.

Someone PMed me to say the codes were probably due to an exhaust leak. I haven't heard any leaks whatsoever, but will check this out closer.

 

[nevada]

That's an awfully steep price...Universal cats are only about 100 bucks and shouldn't take more than an hour or two to weld in. How did the price get so high?

the cats on the v8 are built into the manifold. I don't know how a universal would work...

 

[TeryT]

Just got off the phone with Chris at Scottsdale Muffler and he said he would charge around $650 to replace the right & left cats (way, way cheaper than the dealer!). I told him I planned to replace the two sensors ($104 at O'Reiley's) this weekend to see if that did it. He said he finds that it's usually the cats and not the sensors, and his advice was to just bring it in for the replacement cats first.

I told him I thought I would do the sensors first to see if that worked. Is that good thinking on my part?

 

[rwh963]

Just got off the phone with Chris at Scottsdale Muffler and he said he would charge around $650 to replace the right & left cats (way, way cheaper than the dealer!). I told him I planned to replace the two sensors ($104 at O'Reiley's) this weekend to see if that did it. He said he finds that it's usually the cats and not the sensors, and his advice was to just bring it in for the replacement cats first.

I told him I thought I would do the sensors first to see if that worked. Is that good thinking on my part?

yes, do the sensors first yourself, see what happens. can always re-use them if the cats need replacing. should have new sensors anyway, so money well spent. just make sure you use the right brand. i haven't had to replace any on my 4runner yet, but Denso is typical.

 

[0verland]

Just got off the phone with Chris at Scottsdale Muffler and he said he would charge around $650 to replace the right & left cats (way, way cheaper than the dealer!). I told him I planned to replace the two sensors ($104 at O'Reiley's) this weekend to see if that did it. He said he finds that it's usually the cats and not the sensors, and his advice was to just bring it in for the replacement cats first.

I told him I thought I would do the sensors first to see if that worked. Is that good thinking on my part?

You can try the sensors... but like I said I'm betting its the cats based on the codes. How many miles do you currently have? Glad Chris was able to give you a good price on everything though. I'd like to hear how it all pans out... sensors or cats.

 

[Tanker Yanker]

$5.00 on cats. Sensors are working.

 

[TeryT]

You can try the sensors... but like I said I'm betting its the cats based on the codes. How many miles do you currently have? Glad Chris was able to give you a good price on everything though. I'd like to hear how it all pans out... sensors or cats.

It is interesting that people are generally split between thinking it is cats or sensors. Reading various things and communicating with different folk . . . many sources say the cats should last the life of the car, but exactly what mileage that is no one wants to say. Then other sources say the sensors only last 70-100k. Since my 4R has near 190k, it truly could be either.

So I just replaced both downstream sensors this afternoon and couldn't believe how easy it was! I watched a YouTube video and the guy had his high tech penetrating fluid; he had his Map gas torch; he had his cheater bar and his 3 lb. maul! This guy said you had to be absolutely prepared for battle! Mine popped off with very little effort at all - was the easiest exhaust related thing I've maybe ever done! $100 and a couple hours (mostly in getting the parts and preparing the arsenal of tools I thought I'd need)

BTW - I did check all the exhaust connections for leaks as someone had mentioned - everything nice and tight! (the dealer did tighten everything when they replaced one exhaust part (under a Toyota service bulletin) about 100k miles ago.

So we shall see after I drive it around a couple days. If the lights come back on it'll be time to go see the folks at Scottsdale Muffler.