you sure its not a split EGR pipe in the engine bay? (final exhaust fuses shouldnt smell very bad due to the cat and dpf)
but the EGR pipe splitting is a very common issue . . . and yours is a 2018 so prime candidate.
I've had mine done on bot 2018 and 2017 vans.
Looking at the access its a pig of a job! I have the 204 engine so access isn't so easy Took me a whole day to do. Still not sure the bolts are quite tight enough but seems to be ok. My hands took a right beating. There’s something back there a bit lower down too that looked like the oil...
www.t6forum.com
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