Thirsty for Alfa
Join Date: Oct 2007
Yes, people should indeed do more follow up 'solved' posts!! FWIW, Sorry.
So as suspected, it was indeed the Pre-Cat's. My local Alfa mechanic found a second-hand section of Pre-Cat/Exhaust Manifold that was known to be not noisy, and fitted it. Issue solved. Part was $250AU, not sure on labour as I also had a lot of other stuff done, prob an hour's worth.
I could have never had it done, put up with the noise, and nothing bad would have likely happened (other than put up with the occasional comment from the neighbours), but it's so much quieter now, money reluctantly but well spent.
I took home the old part, someone mentioned I could 'clean' out the inside of the pre-cat, but it's solid iron and not accessible, so really seems like no option except replace the whole section, or get busy with some serious welding equipment.