Question about Catalytic Converter Replacement

[hiptech]

Hey guys hope everyone is doing well. It's been a while since I participated but I have an excuse... I'm old .

Anyway this is hopefully a simple question. I need to replace the cat on our 2000 Accord EXV6. Took it to the mechanic to diagnose a metallic rattle occurring under gentle acceleration. At first we all thought it was pre-ignition or bad gas. Eventually it turned out the converter was the problem. So after almost passing out from the quote I decided this is something I can do myself.

Found an OEM converter online from dealer in MA for a "reasonable" price, ordered it and few YT vids later here I am.

So here's the question, is it good practice to use Permate Anti-Seize compound on the flange nuts & bolts?

Interestingly, the Helm manuals barely mention the exhaust system so no idea what to torque specs on the fasteners
Have both, the main one and the V6 supplement, nada on both...

[Raf99]

I chuckled at that.... But I've never heard or seen Anti-Seize on the bolts/nuts, but I can see why people would do it. Most shops will just zip those out or torch em' if they rusted.

[SSMAccord]

I try to use anti-seize on all of the exhaust bolts to help ease future headaches if you need to revisit that particular bolt in the future.

[hiptech]

Thanks guys, I'll make a run to Walmart in the morning and pick some up. I'll need to grab some PB Blaster to drench the bolts. Someone suggest I do that and let them marinate for the day and then use some more before trying to remove them. The car's been mostly here in AZ so there's no rust but heat can fuse stuff together and it's been 24 years. So I'll keep the torch around too, just in case.

I just hope it's as easy to replace as the YT vids make it look...

[UnicornHondaSE]

Like the other guys said, you can use anti-seize on the exhaust nuts and bolts during reassembly, it shouldn't hurt anything.

On the other hand, some technicians swear that using anti-seize is not good because when it heat and cool cycles over time it can solidify and cause binding and stuck nuts and bolts. I have yet to see that though but I suppose I have not worked on enough various cars.

I've worked on some AZ cars, as opposed to north Midwest salt-belt vehicles and I will say that after living there in the SW for many years you are fortunate and shouldn't encounter much resistance compared to a salt-belt car. In fact, the only reason I did the suspension update for my brother on his Accord was because "Brittany" is from outside of the salt-belt and has no rust on her. Otherwise I would have told him I don't have time or the tools. lol

I recommend to purchase new exhaust gaskets. New exhaust gaskets make all the difference in the world because they are soft being new, they will seal and take shape to the imperfections of the metal flanges.

Definitely soak with pb blaster over night but if it is an original southwest car you shouldn't need to, WD40 for a few minutes in the am should be sufficient.

[hiptech]

Good info much appreciated...
I did order front & rear gaskets along with some replacement nuts so I should be covered.

18160-P8C-A10 - Catalytic Converter
18393-SH3-S00 - Catalytic Converter Gasket
18393-SS0-J30 - Front Pipe Gasket
90212-SA5-003 - Stabilizer Link Nut

[hiptech]

2000 Accord EXV6 Cat Replacement

Looks like my fears were unjustified. After buying both the PB Blaster and Anti-Seize lubricant it turns out I didn't need either. As UnicornHondaSE said, with no corrosion it was a simple matter of removing the heat shield (4 nuts) and 6 larger nuts for the cat (3 front, 3 rear).






I didn't even need the special oxy sensor socket with open wire slot. Instead I disconnected the sensor wire connector and support clip and just removed the cat with sensor intact. After I had the cat on the floor it was just a matter of removing the sensor using a medium size adjustable wrench. I think the whole process took about 90 minutes.





If it weren't for another triple digit, record breaking Phoenix day, it could have been less. Luckily it was only 97° F in the "cool" garage. One thing for certain, as soon as the temps dip into the low 90s. I plan to climb into the attic, finish my wiring, run my line set and definitely install that mini-split I bought 3 years ago, this I vow!!!

It also would have gone quicker if I had access to a lift. Instead I was working under the front end of the car supported by 2 jack stand in a confined space. Especially tough when you're feeling queasy from the heat, lying on your back and trying to wrestle off 6 highly torqued nuts in awkward locations (there's a sick joke in here somewhere).



The (4) smaller (10mm) heat shield nuts were easy, the cat's (6) larger (14mm) mounting nuts, not so much. To remove the cat I ended up using an inexpensive, 14" long flex head, 3/8" ratchet I picked up some years ago from Harbor Freight and never needed, till now. Turned out to be the best tool for the job, the articulated head really helped remove the nuts from the surrounding large awkward flanges!






My goal today is to install the new cat. But the one remaining question is what is the torque spec for the 6 cat bolts?






BTW, can anyone ID these components downstream of the cat?
No idea what this one is...


Guessing this is a resonator?


So if someone can PLEASE tell me the torque specs to install the new cat I'd be very grateful!

[UnicornHondaSE]

Sorry can't help you on torque specs for that year Accord but I will check the manual tomorrow for the 1991 Accord if you want. Lol.

Six highly tortured nuts certainly is a good conversation piece with the lady after a beverage. Lol.

Beautiful undercarriage (use that one also after a second beverage).

I pray that your garage doesn't face west. I know your pain. Most Phoenix garage guys I knew had swamp coolers and even then it was an exercise in futility during mid summer.

The other two exhaust pieces further down I believe, not 100% positive, are resonators for sound reduction.

[hiptech]

In closing this I managed to get it all put together and kind of winged it on the torque. Basically used my impact driver to seal the connections until the flanges no longer had any gaps and then "torqued" them till about 2-3 threads were visible past the nuts. Bottom line, the issue has been resolved, no more metallic rattle!
Just returned the old cat to the dealer in Massachusetts for $23 shipping and a core charge refund of $150 so not a big payday for that.