Ford Flex NOx Catalyst Aging Exhaust Leak

Dude, that sounds eerily familiar! I have a Flex too, and I swear I went through something similar last year. The exhaust leak thing is like a domino – if one thing goes, everything else falls apart. My check engine light was on for ages, and it was driving me nuts! I didn’t even know what NOx storage was before this, lol. Did you notice any change in fuel efficiency or the way the engine sounds?

Interesting. The fuel efficiency seems slightly worse, but it's hard to quantify. The exhaust note is definitely louder, which led me to suspect the leak in the first place. When you had your similar issue, did the error code specifically point to the NOx catalyst, or was it something else? Was the exhaust leak hard to find?

Okay, louder exhaust and worse fuel economy – sounds about right. Yeah, the error code was NOx-related, something about emissions being out of whack. Honestly, the leak itself was a pain to locate; it wasn’t obvious at all. Like trying to find a needle in a haystack, especially without proper tools. I ended up taking it to a workshop. They found a tiny crack in the exhaust pipe near the catalyst. I'd recommend getting it checked out by a professional. Trust me, it'll save you time and frustration.

Thanks for the insight. I appreciate you sharing your experience. I've booked it in with a local shop; they're going to smoke test the exhaust system. There was a small leak which caused the NOx storage catalyst to age faster than expected. Repair cost 265€. Glad to have it sorted. Emissions are a pain!