I decided that at 3 yrs old & 48k miles (10k of them by me over 1 yr of ownership), I would dismantle & clean the EGR valve on my 150CDTi after reading all the threads on this site. I wasn't having any obvious problem and on removing & dismantling it, compared to some of the pics in other threads of similar valves at a range of mileages, it was a pleasant surprise.
Sure enough, there was a thin uniform deposit of soft carbon over the insides of the valve body which was soon removed with a stiff paintbrush & white spirit. Similarly in the manifold bit, only a thin readily moved soft powdery deposit, nothing like the deposit shown here.
When coming to the solenoid drilling/removal part, I observed the solenoid pin was free and moved readily without sticking in any position so I only sprayed WD40 into it a few times, then draining it out, no dismantling of the solenoid being required.
There is no evidence that the valve has ever been changed before under warranty either on the Vx record when I got the car, the car service records or when speaking to the previous owner soon after I got it. I can only assume therefore that perhaps the kind of use the car had in its first 2 yrs before I had it was kind to the engine, lots of miles driven with the engine hot, little stop/start. The car had done 37k in its first 2 yrs & I was a little hesitant thinking it was a lot but perhaps now with this, it's better than 15k of short runs for things like this.
So a good bit of preventative maintenance for another 20k or so, just hope the relatively clean state of these bits bodes well for the rest of the manifold. Putting it all back together, the car ran fine as would be expected.
So, I was left thinking as to whether cars that have these problems early on have been used mainly under conditions which are less favourable to the engine or have I just been very lucky in having an unusually clean running engine?
The only thing I regretted after was not getting the modified gasket set from Fiat.