New quiet lifters
Join Date: Feb 2012
Location: United Kingdom
County: Greater London
The plastic type can, in fact it's the easiest way to take it off and replace it. Undo the manifold stud nuts and 3 allen head bolts on the back, and the plastic plenum can be separated. That exposes enough stud length to remove the studs, and lift off the metal stub inlet containing swirl valves and actuating mechanism, with motor mounted underneath. Removing the studs is needed else the HP fuel pump mounting bracket is in the way.
I'd expect the earlier metal plenum version will also dismantle in situ, but I don't think that design will help with the studs. I've not worked on one, but if not, I can't see much point. Most of the work is done already, and the manifold will be much easier to clean, deal with swirl flaps etc, if removed completely.
It's not an horrendous job, really. The most taxing bit is removing the vacuum oil separator bolted to the back of the block. But even that's not too bad once you know where the 3 bolts are (eLearn has an image) and have tools to deal with them (long sockets). Putting it back is not as bad as expected. I found it easy once I'd taped the bolts into the long socket as a handle to get them started. You can't see much, but mechanical braille is good enough. On mine 2 of 3 mounting holes in the bracket were open slots.
Due to my stupid cockup with wiring (EGR plug and swirl flap motor plug confused) I had my plastic inlet off twice. The second time was really easy, though removing and replacing 10 studs is tedious.