Hoping to get some opinions on my 2014 Prius. I think my cat might be going bad and also noticing an increase in fuel consumption. This car has never thrown a code. Lately, I’ve noticed the exhaust sounds a little louder. (Not as loud as a cat being removed, but like, exhaust leak louder). I’ve also noticed some liquid dripping from my exhaust when running. The liquid also sounds like it’s pooling in the exhaust as I can hear a gurgling in exhaust while running. I’ve also noticed a strong chemical smell coming from my exhaust when running. I have been driving the piss out of this car the past 6 months and have been using it for car camping a lot. Not sure if the exhaust was always this loud and I’m just noticing it because I’m spending a lot more time in and around my car lately. Could be an exhaust leak but with that strong chemical smell coming straight out the tip of the exhaust, plus the increase in fuel consumption, I’m thinking the cat isn’t doing it job like it used to.
When your cat clogs the bolts that connect the exhaust manifold and the cat together are on springs to protect from the movement of exhaust system on rough roads. So these springs will also make room for an exhaust leak when there's too much back pressure from a clogged cat. So if you smell a 1970's pre catalytic converter exhaust smell near the firewall in the engine compartment your flange gasket has failed and it's definitely a clogged cat. There's lots of cat soak recipes online to clean them, but when I learned all this it turned out being a waste of time.