Exhaust leak?

[MGMorden]

Ok - I think I've gotten the oil leak in my Sonic finally sorted out (bad oil cooler).

As a result of having been working on it recently I was checking it over rather intently when I started it up. After it warms up there was a bit of light smoke coming from the bottom. Now, it had been smoking rather badly earlier because of the oil leak, but this was different - it seems to be puffing out in rhythm with the engine, doesn't have that burnt oil smell, and stopped immediately after I shut the engine off (when I was leaking oil the burnt oil was continuing to smoke for 10-15 minutes).

Video:
https://www.youtube.com/watch?v=4Gkut5EIb6U&feature=youtu.be&ab_channel=FrostedMiniTweets

Am I right in thinking this is just an exhaust leak? The pipe there looks pretty obviously rusted and cracked so I'm thinking I'll just replace it. I suppose I could try to weld any hole I find shut but to be honest my welding skills downright suck and a new pipe is $115 so I'd rather just bolt a new one on there.

 

[JTee2017]

Yeah. . looks like a typical flex pipe leak. Daughter's 2014 1.8L developed a crack there and is typical of a lot of cars.
Just be sure to have it replaced with a flex pipe. . not solid pipe. Else it will break again and maybe worse.
As i recall, she just went to a muffler shop and it cost about $140 for the flex pipe including cutting the old one off and welding the new one on.
Call some places and tell then you have a Sonic that needs a new flex pipe . See what price quotes you can get.

 

[MGMorden]

Thanks - got it changed over last night. I just went ahead and bought a new whole new pipe since it was $91 from Rockauto which is less than what a muffler shop would have charged to fix the old one. The rear bolts and O2 sensor were a pain to get out. My cordless impact driver wouldn't budge them. Ended up taking a larger plug-in impact wrench out to it and it loosened 1 bolt and the O2 sensor but the second bolt broke in two.

 

[JTee2017]

Thanks - got it changed over last night. I just went ahead and bought a new whole new pipe since it was $91 from Rockauto which is less than what a muffler shop would have charged to fix the old one. The rear bolts and O2 sensor were a pain to get out. My cordless impact driver wouldn't budge them. Ended up taking a larger plug-in impact wrench out to it and it loosened 1 bolt and the O2 sensor but the second bolt broke in two.

Good work.. It might have been a good idea to replace the 02 sensor also. Not that much more cost and they get slow reacting with miles and reduce MPG. They won't set a code. . . just get "lazy" and slow in feedback voltage to the ECM.
Also. . . tend to make the engine run a bit rich which loads up the catalytic converter.
If I do any exhaust work in the front like that.. . the 02 sensor gets replaced.

While it's still freshly installed. . . might be a good idea to get one and do it. Before the parts all get rusted in place and hard to remove. Now. . they would just come off easily.