Okay, so I've just fitted the 'upgraded' PCV for my E350 CDI. I fitted part A6420102491. This is for the 265bhp engine, not the 231bhp engine that has a plastic body for the PCV valve.
A6420102491 is the upgraded PCV/breather hose, with the new integrated orange seal with 'tabs' permanently clipped on to the PCV hose end. This is only updated in EPC for the ML, S-class and possible R class.
The 'upgrade' ONLY relates to the orange seal on the end where it connects to the batwing I believe, and eliminates the risk of the previous 'push on' seal getting sucked into the turbo.
The part fitted like a glove, and looks identical in every way to the part that was removed, except for the end seal.
I truly believe Merc have messed up here and neglected to flow this 'upgraded' PCV to the E-class, whilst they have flowed it out to the other Class of Mercs that use the exact same PCV and part numbers.
Side-by-side of the removed PCV and the new 'ML350 CDI' PCV
View attachment 109514
New PCV partially fitted down the back of the engine. I thought there was plenty of room to make this swap, but I did unbolt the bracket you can see to the left to allow me to get a hand and tools in more easily.
View attachment 109515
I cleaned up all the batwing and took the opportunity to replace the orange turbo inlet seal and the two orange eliptical air filter seals (the existing ones were either filthy, or brown!). I also inspected the air filters, which look pretty clean, so it will be another 12 months before I look at those again, but I did vac off from underneath (very important that way round) the big bits of debris that had got through (leaves, dandilion flowers etc).
View attachment 109516
All reassembled and cleaned up a little bit, including removing and cleaning the rubber oil filler catch collar, which had every sort of filth and detritus collecting around it. I thought better to do this now, that risk a load of it falling in come oil fill time.
View attachment 109517
Engine cover back on and cleaned up.
I need to do an engine bay detail at some point. It's on the never ending list!
View attachment 109518