Split in exhaust manifold (diesel)
 

Gradually the racket from the engine compartment got really bad, along with the exhaust smell, and the tedium of having to wind up the revs to keep this car moving... I took a look at the work schedule and thought better to inflict the problem on a Bristol (England) BMW specialist. They did a transformative job to get the 16 year old manifold out, having confirmed my diagnosis that there was a perforation in it.

The split is about two and a half inches along a weld seam. Replaced with a non-BMW manifold. Power band has moved back to where it used to be, noise gone, odour in the cabin gone. Amazingly the turbo was declared serviceable - despite near 180,000 miles on this vehicle - I was expecting that it would need overhaul but apparently not. (As a rough estimate, that turbo has spun 14 billion times. These are well made!)

Very happy with this outcome!

Did you get a cast replacement manifold?

These all fail sooner or later. Changed mine for cast one as preventative measure when I installed upgraded hybrid turbo.

Yes - the garage strongly recommended this approach.

BTDT too - as Clavurion has stated, they will all fail sooner or later.

Probably sooner... :rolleyes:

I used the X8R cast replacement from the UK. Pretty good quality and not very expensive.

I think there's a couple of different versions of these available (from various vendors) and it pays to check you get one with the correct sized exhaust ports - the M57N has slightly larger exhaust ports on the head than the earlier M57 engine.