Diagnosing P0420 Code AKA finding exhaust leak in Chevy Cobalt (works for any car)

Some check engine codes, including the P0420, can mean you have a leaky exhaust. Check for leaks before you go swapping parts. Finding the leak is easy and free if you have a vacuum, tape, and soapy water! I show you how to do this.

[@richardp3624]

Shop vac is a great idea. Well done Bubba!

[@JoeSno-f6l]

Great video Than you Hey I was wondering ,what if you have a po420 with a leak before the rear o2 and a higher temp at the upper weld ring than you do at the lower weld ring on your catalyst That's what I have going on. Would you still fix the leak first then check the temps again? Or is my Cat gone at this point?

[@SuperDave5150]

Nice tip! Thanks

[@TheWilferch]

"So I'll be replacing the gasket there"(2:10 - 2:13)...ahh...the camera angle was wonky. WHICH gasket?...exhaust manifold?...intake manifold?....other? Looks like the exhaust heat shield covering a metal flex joint on the exhaust...so maybe an exhaust header-to-pipe joint gasket?

[@chrisavila8527]

What gasket was it you replaced brotha?

[@stephencurry8552]

Awesome. Thanks for the video.

[@charlsseal7273]

Update?

[@LivingForFishing]

probably worked, ima try it because i really want to find out if it’s my cat