forgive me if this sounds noobish but is it possible to just replace one piece of the exhaust system? Or do you have to replace the whole thing?

I think i have an exhuast leak under the car right at the end of the drivers door. When i drive i hear a putt..putt...putt.putt coming from there.

i had a mechanic replace the muffler a while back but apparently he didn't catch the exhaust leak

is an exhaust leak an urgent thing? or can i wait and save up some $$$ to do it?

I don't smell exhaust when driving the car.

 

To locate leaks, have someone block the tailpipe with a rag while the engine idles. You will hear a loud hissing from the leak.

Yes individual parts can be replaced. If you have an EX type system with the catalytic converter under the car near the firewall, there is the so called "B pipe" which goes from the converter back to about the rear wheel, that is then connected by a flange to the muffler / tailpipe assembly.

Though my experience has been that as soon as one part gets leaky, it's best to replace everything after the converter to the back and be done with it. Everything there tends to rust out at the same time. The front pipes before the converter can last much longer.

 

Yep you can replace one part at a time unless it's already been worked on and the shop welded the pieces together.

I replaced my B-pipe and muffler separately and as long as you get the bolts and gaskets it's a very easy change. It was almost appalling to me why it would cost so much to get it done at a shop. It's literally 5 bolts, and yea they're rusted solid so all you do is spray them with PB blaster and if they still dont come off you just break them off and replace. I bought a honda B-pipe and muffler and it was very reasonable to do myself and I knew it would fit and last a long time.