Muffler replacement

I have a 2004 Nissan Sentra and I need to replace the muffler on the car. It wouldn’t be to bad of a job but I’ll be dealing with really rusted bolts and flanges.

What’s the best way to go about things, should I put a cutting wheel to the muffler side bolts on the flange because I never put heat on something this bad and rusty.

I think my main problem would be connecting the new muffler to the other flange if it can be used. But if the other flange can be used and in rough shape they do sell flange repair kits and split flanges to strengthen things, how well do those work or what’s a better method to secure a rusty flange.

Now if the flange on the other pipe is garbage the best thing would be replace the other pipe but I’m dealing with some rusty connections that I might not want to mess with so I’m curious if I come across this, if I can instead cut the pipe on a straight part of the pipe and cut the new pipe and put a connector on it, so how well do connectors seal with muffler clamps on it. Because I can’t make a straight connection from muffler right to the other pipe, it curves where the flanges are. I don’t have a welder and I’ll would be doing this in my garage at home.

That’s the scenarios I think I might come across, but what is the best way to do a muffler replacement on my car? I plan on using Walker brand.

Muffler work is not fun with limited space to work and rust flakes falling in your eyes. Actually by the time you get all done, having a shop do it is not all that more expensive. At any rate, you cut everything off and start new back to good metal wherever that is. An angle grinder with a cutting disk on it is what I have used if you have room. The other thing is, I have found the dealer parts are a thicker metal than what you would get at a parts store. More expensive yeah, but better quality. A lot of mufflers now are lifetime stainless steel. I haven’t had to replace a muffler in a long time.


The last time I replaced a muffler was on my 1978 Cutlass. It took me 3 hours. I bought the muffler at NAPA. When the muffler needed replacing 5 years later, I went to an independent exhaust and muffler shop. The total cost was less than what the muffler cost me at NAPA and the job was completed in 10 minutes.


Have an independent shop do it while you wait in a warm waiting room drinking free coffee.


Exhaust work is annoying but not that hard with the right tools. Repair depends a lot on where the failure is. Modern stainless pipes and mufflers usually fail at the seams or weld joints. I see from RockAuto that the muffler has a flange on it to attach to the mid-pipe.

Soak it with PB Blaster or similar and wait overnight. I usually hammer the correct 1/2 socket onto the rusty nut and apply generous torque with an 18 inch breaker bar. I hope it breaks off, or unscrews. Either way it is getting replaced. If neither work, cut it off with a friction wheel. You may have to hammer out a pressed in stud. If the mid-pipe flange is broken so you can’t install the muffler, cut BOTH flanges off and use a stainless band clamp to hold them together.

Don’t worry bout cheaper aftermarket parts, they won’t fail before you sell, scrap or trade this for another car.

I called for prices on just a muffler replacement and it’s $300 - $400 and it will be more if they don’t think they can connect to the other flange.

I’ll probably go with the more expensive muffler which is $100 and stainless steel.

The muffler is pretty accessible, take off the back passenger wheel and the flange is right there. I’ll have to get underneath to cut the bolt on the other side of the flange because bolts look nasty and probably won’t unscrew off and unhook the muffler off the hangers.

Mustangman: I might need to use a stainless band clamp or a connector with muffler clamps on it but how well do they hole and seal? But if the flange is good enough to connect to, how well does it need to be cleaned to get a good seal?

If you can get the bolts off at the flange, then it’s just a matter of getting new bolts/nuts, a flange gasket, and attaching the new muffler.


I went to a bender place, got a muffler with a lifetime warranty and pipes for less than I could buy the parts at NAPA, years later the muffler went out, I got charged less than $10 as muffler clamps were not covered. They also noted the catalytic converter was split, and welded the split for $10.

How did they weld up a split catalytic converter, without burning up the mat?


No Idea, but never had any trouble passing emissions testing. What is a mat?

Applying torque to the bolts it really doesn’t take that much to break them off. Of course if it is a flange connection then use the gasket and tighten well. If its a regular pipe to pipe connection, you tighten the clamp so that it compresses the pipe to a groove to make it sealed. Just use new bolts for the flanges and new clamps.

I called midas and some local shops and I got no less then $300 for just muffler replacement alone and it might need other work to connect the muffler for them.

if I have to cut and put a connector on the other pipe, if it might need a weld around the pipe or 2. I just asked on prices to put 2 welds around a pipe and there were shops saying it would cost $100

The mat is what isolates the converter substrate from the can. (converter body)


It looks like insulation, purpose? Maybe just reducing heat transfer to the catalytic converter shell?

It prevents exhaust gases from flowing between the substrate and the body.


It takes me about 20 seconds to cut through a 1/2 inch bolt with an inexpensive dremmel tool. If the rusty bolts won’t break free right away, just cut them off and replace w/new. Suggest to wear a full face shield when working under the car, esp on the exhaust system. Getting even a tiny particle of rust/dirt in your eye can bring the job rather quickly to a full and unpleasant stop.


I’d use a band clamp rather than a connector and conventional clamps. The band clamp conforms better to somewhat wonky surfaces and seals well. I’ve used them for years on pipe-to-pipe joints the same size as well as pipe-into-pipe slip-over fittings. There are 2 kinds of band clamp designs, straight and stepped for each of the 2 joints. In your case the un-stepped models should work. This assumes you can get the correct size band clamp for your pipes.

If there is an internal flange that mates with the muffler, then just clean the loose lumpy rust off and you should be fine. If the flange has a gasket, knock off the loose rust and hit it with a sanding disk or even a file just to flatten it out a bit.

Good Luck

My wifes 96 Accord was the last vehicle I had to replace the muffler on. 98 Pathfinder and 05 4runner - both went beyond 300k miles on original muffler. I think 1997 was the first year vehicles were required have exhaust systems last 50k miles and most started using stainless.*15317

I just saw this product being using in a youtube video and it looks like this would be plan B if the inter pipe flange is garbage. But I would have to put it on a round part of the other pipe maybe some distance away because where the flange connects is it curves. Anyone use one of these and how well it works?

Is any seal required or better off using, with the gasket when connecting the flanges?

If it has a gasket, use it all by itself. There is exhaust sealing past available at the auto parts store that can help with rusty surfaces.