Flange on left header not welded?

[pbonsalb]

No. It is the way bmw designed it. There is a cone shaped gasket that seals between the flanges.

If the E46 M3 midpipe to rear exhaust flange fits the E90 M3 header pipe and cone shaped gasket, is there enough meat on the flange to simply drill the bolt holes longer?

[Insomniaroy]

I keep getting leaks even after replacing both gaskets * cleaning the flanges , torquing cold and retorquing cold after few cold-hot cycles.
All brackets, clamps and exhaust hangers seem ok but I still suspect under heavy braking the midpipe slides forward just a little bit over that left header connection, destroying the gasket.
Would it be safe to weld the left flange to the header ? Maybe it is not welded to allow for expansion/contraction because otherwise something will crack ? In this case I will mod the bracket from gearbox to exhaust. This is my 2nd M3 that has this recurring issue and I'm on stock exhaust setup (+OEM end box mod).

[2011_M3]

Originally Posted by Insomniaroy

I keep getting leaks even after replacing both gaskets * cleaning the flanges , torquing cold and retorquing cold after few cold-hot cycles.
All brackets, clamps and exhaust hangers seem ok but I still suspect under heavy braking the midpipe slides forward just a little bit over that left header connection, destroying the gasket.
Would it be safe to weld the left flange to the header ? Maybe it is not welded to allow for expansion/contraction because otherwise something will crack ? In this case I will mod the bracket from gearbox to exhaust. This is my 2nd M3 that has this recurring issue and I'm on stock exhaust setup (+OEM end box mod).

Did you ever get it fixed I'm having issues with the driver side header to my test pipes and I just bought gaskets and put the on today and still has a leak. I put sealant and exhaust tape to try and fix it but it still leaking but not as much anymore and I haven't go into limp mode so far and I drove it for 20mins

[Insomniaroy]

I didn't fix it but didn't notice any obvious leaks during winter (windows up). Also got my anual checks done recently and no remarks about any exhaust leaks , although a small leak would go unnoticed I think.
Maybe it fixed itself this time ?

[GearKid]

Originally Posted by mitch32

Hello,

I removed me exhaust today and the left header doesn't have a welded flange, the right header's flange is welded on and can't move. Please see pictures below.

I just recently swapped out my midpipe and noticed the floating flange on only one side. It's definitely by design in order to ensure the exhaust system lines up properly without putting excessive stress on the headers.
If there's any leaking then the gasket isn't seated correctly or there's a defect in the mating surfaces of the midpipe or header pipe. The flange won't prevent a leak whether it's welded or not. It's designed to compress the gasket into the midpipe and around the exhaust pipe.

Here's the link from ESC Tuning for the gaskets

https://www.ecstuning.com/b-genuine-...h/11627830668/