On the way to Ultimate BMW on Sunday were in a little convoy, battling horrendous road conditions from the rain.
Loads of standing water but I was avoiding it, not running through any obvious puddles.
1hr in my car started to sound like the centre section of exhaust had fallen off.
It was really loud, and the car felt a little sluggish. It sounded horrific.
Very noisy blowing/booming from underneath.
We stopped and checked (in the pouring rain damn it), the exhaust was present.
Popped the hood, and it was deffo a very loud blowing/puffing noise when revved, and the revs felt sluggish, coming from under the drivers footwell area.
Not anything mechanical from the engine, no knocking, ticking or rumbling.
No engine check light, no steam or smoke.
Within 5 mins of setting off and driving slowly to the meet-point, it was back to normal. The glorious straight 6 sound track returned and the car response was normal.
All was fine on the next drive from meet-point to the show.
All was fine again when driving home, no issues and the car performed perfectly.
Until...... Another long stretch of standing water. A couple of inches deep for probably 20mtrs.
We drove through it very slowly (3mph max) and halfway through, instantly the car returned to sounding like the exhaust had fallen off.
Same symptoms, rediculously noisy, exhaust related, it was blowing/coming from underneath.
Within 5 mins the noise went and since then it's been running like a dream.
I took her out again today and no problems at all, running perfectly.
What could cause this, water ingress into the cats/sensors??
It honestly sounded/felt like I'd expect if the exhaust was filled up with water. But if water ingress to this extent was occuring, I'd have an obvious blowing exhaust.
