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The Mondeo manifold sagaI'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 manifoldsI'm not sure exactly what year this was fixed (if ever), but the earlier Mk3 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). 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 failsThe 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 seperate 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 Inlet Manifold Diagnosis Also, one of the other fordmondeo.org users (CoC) has posted some excellent photos of the two different butterfly or swirl plate designs in this thread: New and Old style butterfly plate photos Note: replacement butterfly inserts are now available for the new type manifold - see the upper picture in the new/old link above. I have not used these myself, but according to reports on the Mondeo 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 intruduced 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) |
![]() This is the manifold, as removed. As you can see, two of the butterfly plates are missing - they were in the head ports |
![]() This is Port 1, the butterfly plate is out at one side but the stub of spindle (towards port 2) is stopping it falling out completely. |
![]() This is Port 2 - in this one the spindle had broken completely at both sides of the butterfly plate, and the plate complete with shaft was in the head port. |
![]() The butterfly plate from No. 4, found in the inlet port. |
![]() This is a view of one of the ports, showing the crater that started out as a bearing hole for the bush on the end of a butterfly plate. |
![]() A close-up of the same thing.. |
![]() The set of inserts that support(ed) the butterfly plates, plus the bit of spindle from port 1. |
![]() A closer shot of the shaft from port 1. |
![]() This is the side of a butterfly assembly, clearly showing the wear of the hole and bush. |
![]() And it's close-up view. |
If you need any more info on this, you can contact me via the Talkford.com forum (username rajenkins). Or, as a last resort, email me |
Page last updated April 2019
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