So with valuable help from the forum (and Joe H the picture of the V clamp really helped) I have managed to remove the EGR and Cooler assembly the question now is what to do next.
The valve is quite clean because I cleaned it thoroughly about two years ago and again last week.
Some contributors have talked about plastic gears that strip so the valve won't work and I presume these are in the black plastic electronics unit with Pierburg printed on it. A new one of these assemblies is a whole load cheaper than a whole new EGR valve so is the way to go? Is there any way I can test the functioning of the EGR valve or this electronics unit?
I have removed the black electronics unit. Despite soaking them in WD40 all 4 torx screws broke on trying to undo them so these will have to be drilled out. There is some evidence of water seepage/corrosion underneath the electronics unit (see picture) but it doesn't seem to have got past the seals on the prongs and into the motor unit. This electronics unit has a plunger that rests against the cam assembly on the end of the EGR valve shaft. This plunger can move freely and it sounds as it it is moving a spring mechanism inside the casing. I assume the EGR valve opens and closes via the cam on the electric (stepper?) motor. Then as the valve moves the plunger resting on the cam works a gear to provide feedback via the electronics to the ECU.
I don't think the EGR motor or valve stem has seized but I can't see how to test the EGR valve for movement. It looks as if the outer casing of the cam assembly is welded to the top of the EGR valve shaft during manufacture so to get it to move you need to rotate the motor. But I am wary of just trying to stick 12V across the terminals to see what happens.
So does anybody know how to test the EGR valve or has anybody had experience of just replacing the electronics unit?
http://www.partsforvolvosonline.com/...oducts_id=8461
Any advice on how to proceed from here would be appreciated.
Many thanks, Chris.
BTW For anybody trying to do this same job in the future I will describe how I managed to get the EGR valve out and in particular the V clamp attaching the Cooler to the Flexible pipe.
Firstly to get access to the EGR valve I followed the instructions in my Haynes manual, removing the air-box and throttle body, but then it says undo the four screws and remove the valve - simples. But on the 185 Euro IV D5 it doesn't work like that. I undid the electronics connector and the vacuum pipes at the front and the manifold connecting pipe. then I removed the black plastic pipe going from the turbocharger to the airbox/MAF sensor pipe and undid cooling pipes at the rear. This improves access to the rear EGR cooler mounting bolt and the V clamp from being impossible to difficult. I completely undid the jubilee clip and pushed back the tab part as far as I could. To remove the V clip you need to separate the top and bottom halves but the jubilee clip is welded to each half of the V on the most accessible side (i.e. the bit you can see) so there is no point in trying to push them apart from this side. I soaked the V clamp in WD40 overnight, then took a small flat bladed screwdriver and, coming in from the rear bulkhead side, placed it between the two halves and pushed/levered up. This loosened the top half and in a similar way I then loosened the the bottom half. You can't easily see this as it is on the RHS (towards the centreline of the car) so it is mainly done by touch but it was surprisingly easy and worked first time for me.