My 2008 4Runner ended up with P0420 and P0430 at about 320K miles last year. I tried the various options (cat cleaner, replace O2 Sensors (sensor 2, etc.) to no avail. Finally, I just hooked up my OBDII sensor full time and reset the light every drive. Factory manifold Cats are 17140-31250 (right) and 17150-31250 are something like 744.60 MSRP for a total of $1489.20 for the set. Best price I could find on discount for the factory cats was $545 each ($1090 total), so I decided to take the chance. I trolled the eBay listings and at that time could find a not-quite-the-lowest-price SET from a Canadian manufacturer (quality-exhausts) for $198 delivered. Searching for them today and the prices have dropped to the $130 range for a
SET! Should have waited.
I ordered
these and they were timely delivered to me in Kansas in early
February 2022. The packaging was barely adequate and seriously beat up. At least they had some padding.
It came with gaskets and hardware (that I would not use, even if it had not been mangled and mostly lost in the holey packaging), but I decided to get all the hardware from the factory. I was paranoid about removing the nuts and studs as nothing makes a simple day job replacing manifold cats into a nightmare like a broken exhaust stud.
So, I started basting them in penetrant and looking into an induction gun.
I also decided to secure the new things I needed to do the R&R that I did not already have. This included the E8 and E10 external torx (star) sockets for the exhaust studs on top and bottom, a factory set of gaskets (2 "gasket, exhaust" p/n 14173-31010), new studs (12), and nuts (12) for the manifold to head connection and new exhaust gasket (2), studs (4), and nuts (4) for the manifold to lower exhaust. I also got ½ in. impact sockets for the relevant nuts (12 and 14mm) to supplement my standard chrome sockets. Finally, I bought two new A/F sensors (
Denso 234-9026 Air Fuel Sensor $112 each on Amazon) and one new O2 Sensor (
Denso 234-4260 Oxygen Sensor, $48.04) as the other O2 sensor had been replaced not long ago. Denso is the supplier to Toyota on these.
Fast forward to January 202
3 (
almost a year later) and I had been resetting the MIL light every drive, had been spraying on penetrant for a long time, and finally worked up the courage to tackle it. I decided to forgo the induction gun and went at them with a tight-fitting socket and long breaker bar, doing everything by hand. I started on the easier passenger side (more room to work). Five of the nuts came off without a hitch and the 6th one came out with the nut and stud frozen together. Of note, I put the front up on a jackstand and removed the front wheel for access. The lower row of the manifold nuts was easily accessible from the wheel well area, just use some extensions and maybe a wobble head socket. The lower end fasteners all came off with the impact gun from under the car.
I decided to remove the 5 remaining studs and used the E8 with a 1/4 drive socket wrench. Four of those came out but made me nervous. The last one refused to budge, but the exposed threads were good and after test fitting a new nut on it and running it all the way down and up again I decided to reuse that one. I then cleaned the head face with some scotch brite saturated with brake-clean. I put 5 new studs in and used silver Permatex anti-seize on the threads before running them into the head. I hand tightened them in place and put the new gasket over the studs.
I turned to the cat at this point. I tried to remove the A/F sensor (B1S1) from the old cat but it was rust welded and required heat and penetrant. While it did come out the threads were trashed; already had new A/F sensors so it was no big issue. I installed the A/F sensor in the new cat now, as I thought I had room to maneuver the thing in with the sensor installed. I took the lower studs off using the E10, mainly for reference as I had new studs. I installed the new studs in the new lower flange using Permatex anti-seize.
The new Cats are not as big of "cans" as the factory ones (back to that in a second). So, the passenger one went back in easily. I dropped the lower studs into place in the flange and then lined up the manifold face with the studs on the head. It took some prying braced on the back of the pump housing to get the holes lined up with the studs, but once lined up a tap with a dead blow mallet got the manifold seated. I finger fit the 6 new nuts on the studs up top and snugged them into place. I set up my 3/8 drive torque wrench up for 22 ft-lbs and tightened them all up.
I moved to the lower end connection and at this point realized that I forgot to put the exhaust donut gasket in there. I pried the faces apart and using a 1/2 extension to hold the faces apart, got the gasket seated. I then torqued these to the 40 ft-lbs and reattached the hanger bracket. While down there I could reach and reattach the B1S1 sensor to the harness. The downstream O2 sensor (B1S2) was not budging, so I doused it in penetrant.
I started it up the took it for test drive. It was still throwing the P0137 as the B1S2 sensor was still bad, but no longer threw the p0420. As soon as I got it home I tried to loosen the B1S2 and it came out having heated up. Ran a thread chaser and reinstalled the new sensor. Test drive confirmed no codes on Bank 1 and it has been several weeks now.
Before I go to Bank 2 R&R I want to talk about the cats. The factory part is obviously a larger cat that the aftermarket. The factory cat is approximately 5.25 inch diameter by 14.5 inches long. This yields a radius of 2.31 inch and a volume of catalyst of 88.01 cubic inches. The aftermarket has a 4.25 inch x 13.5 in. catalyst resulting in a 2.14 inch radius and a volume of 61.18 cubic inches. That is about 69.5% of the volume of the factory part. I got about 300K miles out of the factory cats (between 3.4 and 4.9 cents per mile) so I suspect I will get about 200K out of this set due to the reduced volume (at about 1 cent per mile). I am a fanatic about my 4Runner, but I don't know that even I will take it to 500K, I mean something major is ever more likely to go haywire, knock on wood
)
The Bank 2 (Driver's side) cat has a lot more "in the way" up top and down below, so I left it for a week later. After removing the front wheel with the truck on a jackstand, I found that the strut tower is more in the way on the driver side for at least the lower nut on cylinder 2. But, I got all 6 off without a hitch and none of the studs came out with the nut. I later decided (after test running a new nut up and down each stud) to reuse all 6 of these studs, but had new ones just in case.
The lower flange nuts came off without a problem, but the mounting bracket bolt was really rusted and I probably could have used an induction gun at that point. However, I just removed the two upper bracket mounting bolts and removed the manifold with the bracket attached. You have to contend with the forward drive shaft so it took a little Tetris thinking and a prybar to wiggle the cat out with the bracket attached, which is done form below. Once out I tried heat and ended up sawing the bolt head off to free the bracket for mounting on the new manifold. I also had new flange studs but could have reused one of the the two as the other one twisted off at the external hex base when I was using the breaker bar and heat to get it free. This side's A/F sensor came off without a hitch and probably could have been reused, but I had a new one that I installed.
Cleaning the head face was more of a challenge with the studs all remaining, but its accessible from the wheel well and it turned out well. Reassembly was as with the passenger side, but I did wait until the body was wiggled into the space before screwing in the A/F sensor. The exhaust flange (lower) studs I installed with anti-seize. There is less to pry on on the driver side, but carefully using a bar I got the studs in the lower flange and lined up the upper manifold on the exhaust studs and a few taps with the handle of the dead blow hammer and it was seated.
"Finger tight-ing"
the new nuts was pretty easy, as was torquing 4 of the 6 nuts. I did do most of these from the wheel well using a 1/4 inch deep 12mm socket and a knurled extension to spin them on an then a 3/8 torque wrench. Getting a torque wrench on the lower nut on the #2 cylinder was made difficult by the strut tower, but with enough extensions and a wobble elbow for the socket I could get it pretty straight on and minimized the off-angle torque loss. Once it was basically tight, I was able to back off and get a deepwell 12mm and torque wrench on them from above to confirm torque.
Final note on the downstream O2 on the driver side. This one is the harder of the 2 downstream sensors to R&R, so if you need to change yours out you have more access while the manifold is out. In my case I had previously replaced this one (20K miles ago) so did not do so at this time.
It's been a few weeks now and it's not throwing codes on either bank and has passed all its diagnostics. Not to jinx myself, but I think I got it done without a serious problem. Whew!
I KNOW there are factory parts purists, and I am normally one, but the price difference was just too great to not try to use the aftermarket ones. The price for the aftermarket cats has dropped by about $60 a pair since I bought (that is a 30% drop) which would make it even more attractive today. For me it was worth it and I would probably buy again from the seller in Canada that I used, but YMMV.
Anyone know WHY Catalytic Converter prices have dropped 30% over the past year? I am curious, given that most everything else (except Toyota brake rotors, oddly) has gone UP.
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