I did a thing!
For a while now I’ve been increasingly paranoid about an exhaust leak mid-front of my Z4M. A tapping/ticking/chuffing sort of sound which was prominent when driving slowly past a armco barrier etc. I couldn’t see any issues underneath so left it alone.
Whilst enjoying some rum, a spot of googling found some forum hits in America where the manifold nuts had loosened off with time and created a similar sound. After many grazed knuckles and a trusty 13mm deep socket and extension I found all of the nuts were not snug. Now they are done up it’s so much quieter running and low down response is much better. Dare I say even the infamous idle dip/bounce may be better too - suspect the car needs to relearn its adaptions now. Hope this helps anyone with similar
Tips:
Removing the heat shield needs 3x13mm bolts taking out and 1x10mm. If you remove the cross brace and v brace and disconnect the plastic pipe going to the air pump at the air pump end. The two cables for the o2 sensors easily unclip. You then can rotate the heat shield down and around and spring it out past the other heat shield.
A head torch is very helpful, each of the branches has 3x nuts on them and for some you will work blind , or need a stubby extension on a medium sized ratchet. I used deep 6 point sockets for the job.
Do not over tighten the nuts and snap the studs, snug up by hand using a medium ratchet, mine needed 1/4 turn typically.
When putting it all back the rear bolt on the heat shield is a pain in the butt, you have to thread the bolt through my only the heat shield itself (working blindly, but also through another bracket which holds the cables, it’s hit and miss to line it all up).
Hope this helps
Adam
For a while now I’ve been increasingly paranoid about an exhaust leak mid-front of my Z4M. A tapping/ticking/chuffing sort of sound which was prominent when driving slowly past a armco barrier etc. I couldn’t see any issues underneath so left it alone.
Whilst enjoying some rum, a spot of googling found some forum hits in America where the manifold nuts had loosened off with time and created a similar sound. After many grazed knuckles and a trusty 13mm deep socket and extension I found all of the nuts were not snug. Now they are done up it’s so much quieter running and low down response is much better. Dare I say even the infamous idle dip/bounce may be better too - suspect the car needs to relearn its adaptions now. Hope this helps anyone with similar
Tips:
Removing the heat shield needs 3x13mm bolts taking out and 1x10mm. If you remove the cross brace and v brace and disconnect the plastic pipe going to the air pump at the air pump end. The two cables for the o2 sensors easily unclip. You then can rotate the heat shield down and around and spring it out past the other heat shield.
A head torch is very helpful, each of the branches has 3x nuts on them and for some you will work blind , or need a stubby extension on a medium sized ratchet. I used deep 6 point sockets for the job.
Do not over tighten the nuts and snap the studs, snug up by hand using a medium ratchet, mine needed 1/4 turn typically.
When putting it all back the rear bolt on the heat shield is a pain in the butt, you have to thread the bolt through my only the heat shield itself (working blindly, but also through another bracket which holds the cables, it’s hit and miss to line it all up).
Hope this helps
Adam
