Sorted this today - no more smoke! Car starts and idles okay, I'll be giving it a big drive tomorrow as a good test
Word of warning for W212 owners - it's considerably more tricky than W211 because there's a bracket clamped on top of the PCV which makes access to two of the three bolts very, very tricky. You
need a long, thin, flexible way of attaching an E10 torx 'through' the bracket, to gain access to the two bolts - I had to improvise and cobble together a bunch of adaptors, but was so glad that I was able to sort it and didn't have to put it all back together and go buy some more tools!
Mine took a coulple of hours as I... ahem... I removed two bolts that were unbelievably tricky to get to and remove at the back of the engine, thinking they were the ones I needed to get off to get the bracket out of the way... but they weren't... so that was an utter waste of time! I also didn't really have anything to go on for a W212, other than that pretty bad video above. It's hard to describe, sorry!
Oh and finally - a telescopic magnetic torch tool is very useful as it's very likely that you're going to drop stuff (bolts, nuts, sockets etc) into the undertray...
Cheers,
Ed
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