The page below is updated as of April 2020.
The 2002 Mondeo that the 2007 article relates to was sold in 2015. It's replacement is a 2007 Ghia X, again a 2L Duratec.
This also had a noticeable manifold rattle at the time of purchase in 2015 and the swirl plates were disabled by removing the vacuum actuator connection. I eventually stripped the manifold to check it properly and clean the PCV valve etc. during 2019.
I found there was some wear of the swirl plates and spindle bearings, giving about one millimetre of play - a vast improvement over the original type bearing & spindle arrangement, but still giving a rather annoying rattle. I removed them and blocked the actuator hole as the replacement parts cost was just unreasonable.
The Mondeo manifold saga
[2007 Article text and photo gallery, with some updates for broken or changed links]
I've run Fords for a good few years, first Sierras and later Mondeos.
These have been generally been reliable, economical and good performers - until now.
Mondeo Mk3 2L Duratec engines can eat their inlet manifolds
The earlier Mk3 Mondeo Duratec engines have parts in the inlet manifold which can wear out, eventually become detached and be sucked through the engine, with possibly catastrophic results (ie. new engine required).
[A re-designed manifold was introduced sometime around 2003, which has better bearings on the swirl plates. I do not know for sure it this is a 'cure' to the problem, or just has a somewhat longer life before failure.]
In my case, the final failure happened one morning as I started the car in the garage, so it was only running at tickover for a few seconds after the manifold bits went in to the engine and it seems no serious damage was caused to the piston or valves.
I'm probably one of the lucky ones, I'd only spoken to a few people about it before someone said it had happened to them while driving and in their case the engine had to be replaced.
What actually fails
The inlet manifold has an extra set of butterfly valves set in to the flange where it attaches to the cylinder head. These are controlled by a vacuum actuator and appear to be designed to deflect the airflow towards the fuel injectors to give better mixing under low throttle / high manifold vacuum conditions.
The problem is that each butterfly has relatively small moulded-in bearing bushes at the ends, and over time these wear away. Once the bushes are worn through, the long square steel spindle that runs the length of the manifold (to connect the butterfly plates to the vacuum actuator) also starts to wear away at the points it touches the manifold tube walls, and eventually breaks at one or more of these points.
In mine, the steel spindle was in four separate pieces, one of which was in number three cylinder.
This was only the final failure. Two of the butterfly plates were rattling about in the inlet ports and one of these still had another bit of the spindle in it, with the ends nicely rounded over purely due to it bouncing about against the port walls.
Update: For further details on diagnosing the fault and removing the manifold, read these articles on www.fordmondeo.org / www.fordwiki.co.uk
There is an article on Talkford showing some details of the various shaft bushings etc. here
Replacement swirl plates and bearing bushes for the "updated" manifold version are available from Ford dealers. I have not used these myself, but according to reports on the Talkford forum, they will directly replace the butterfly assemblies on the original type manifold. They apparently do not relate to the old manifold in the Ford part database, presumably as they were not introduced until after the original manifold was discontinued.
A set of these is a fraction of the price of a replacement manifold, but do check that the metal spindle and actuator etc. are still in good order before fitting them - a new manifold is cheaper than a new engine!
The pictures - click an image for a larger view
(For reference, the car is was just under six years old & had always been serviced by a local Ford main dealer)