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Good day everyone. After 236k miles, the exhaust system on my 91 Accord EX needs replacement. I figured I might as well replace the catalytic converter too as it’s the original one on the car. I’m purchasing a magnaflow direct fit catalytic converter and their stainless steel exhaust system to pretty thinks up a bit.
I’ve already sprayed down the muffler to resonator bolts with PB blaster along with the cat to downpipe nuts. However, would it be easier for me to remove the whole system from the downpipe back, then take it apart, or leave it on the car and disassemble?
Also, how is the cat attached to the downpipe and resonator pipe? Does it use studs and nuts similar to a hub and wheel setup where you can press out the old studs? The magnaflow directions say to reuse the old hardware, but how??
Just need some clarification and guidance to help make this easier.
Thanks guys, and Eric, keep up the great work!
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IMO if you can get the car high enough to clear the downpipe and slide the whole system out, that would be way better than trying to work under the car that’s up 15″ from you. Especially if that stuff has been together for 20+ years.
If the system will be new. the only thing to reuse is the hanger location hardware. I would use a saws all and cut the system
out from the cat back. this way you can compare old to new. C8-)I would cut it out in sections or remove it as a whole unit.
If you dont have access to heat and impacts tools, expect some possible broken bolts.
I don’t have much to add except that, man, do I hate exhaust work. The last time I did anything involving Honda exhausts, the downpipe was secured with nuts and a stud that you knock out with a punch. But if you aren’t replacing the manifold, you won’t have to worry about those studs. If it were my car, and you are replacing everything from the downpipe back, then I would focus on getting those fasteners apart, and removing the system as a whole unit as well, because, like I mentioned, I hate exhaust work. Doing it with the whole system laid out on the ground vs trying to get 20 year old bolts apart over my head with rust falling into my eyes sounds awesome.
Sounds like the way to go to is removing everything beginning with the downpipe on back in one piece. The header to downpipe bolts have previously been removed when replacing the oilpan gasket, so those should be good to go. I plan on buying new hardware anyway, so I guess a trip to lowes or homedepot is in order. PB blasting things a few days before I begin probably can’t hurt either.
I don’t have access to a torch (except my propane one used for soldering plumbing) or a sawsall, so it’s going to have to be my hand tools and force, FUN!
Thanks for the help guys!
I was in your exact same position a few years back, only it was a 96 Accord. A friend of mine suggested buying a reciprocating saw and it turned out to be one of the best investments I ever made. (I bought a Craftsman at Sears). For an old exhaust like yours, it will be much easier to just cut the whole thing out, starting from the back and working up to the cat. A reciprocating saw can do that in a matter of minutes.
If you have never used one, just be careful about where the tip of the blade goes as it can fly back at you if you are not paying attention. Use goggles, a dust mask, or run a fan so it blows the metal dust away from you.
As for the hardware, it will be very rusted and most of the bolts will not be useable. Just replace all the old stuff.
To answer your other question, I would recommend going to the Majestic Honda website, as they have factory drawings of how all of the parts are arranged. I frequently print these out when I am doing a repair (and ordering parts). When I replaced my exhaust system, I printed everything out and it was a tremendous help in keeping me organized.
Hope it goes well.
I don’t recommend replacing the cat with an aftermarket unit, just check the posts to this forum about how many people have tried that on Honda’s only to have a P0420 afterward. If you don’t have a code for it leave it alone.
+1 on just cutting off the pieces to make your life easier. I don’t have a lot of faith in penetrating oil however especially with those miles, this video shows how I deal with it.
Thanks everyone for the help! Sounds like I may need to drop the whole system and purchase a reciprocating saw now to do some cutting.
I do have a question about the catalytic converter though. Since my car is OBD I, I didn’t think a code existed for catalytic efficiency or does it?
My main reason for replacing the cat was due to age and mileage. Car runs great, but I’m worried that if I only replace the exhaust from the cat back and then the cat starts to disintegrate it will clog up my new piping.
Am I over thinking it and should I just return this new catalytic converter?
Thanks!
Do you have emission testing or inspection where you live?
If your replacing the entire exhaust, i would also replace the cat.
I agree with Eric about not using an aftermarket cat. If the car is running fine, I wouldn’t replace the OEM unit. With your car being a ’91, it PROBABLY won’t have an after cat o2 sensor but a quick visual inspection will make you certain. The only concern with a failing cat beyond inefficiency that I’m aware of is the innards getting clogged and swelling shut, pinching off your exhaust.
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