Well, i rebuilt my EGR valve and now it's 10 times more sturdy than the original... letme expand on the story:
I wasn't getting any CEL but the engine block behind the EGR/ASV combo was all "splattered" with black oily sooty thingy, and the assembly was all gunky with the same nasty mix.
So we(my father and me) took to cleaning the entire intake, removed manifold, asv, EGR, the whole shebang...
So, cleaned intake manifold, ASV was a whole other issue let's leave that apart...
When we got to the EGR sure enough it shown streaks of a "leak" on the vacuum seal equalizing ports, midn you there wasn't any vac leak so the diaphragm was working ok.
on further inspection, turns out the shaft loses seal and allows the (high pressure) intake mix(that has oil gasses in it..) to blowby and that was getting my block all sprayed..
needless to say, this is a bad thing as it's leaking pressure which means that either the turbo has to work at a higher duty cycle to compensate or you get lost air which means engine will run rough/bad due to lean mixture...
So... no way i'm paying for a new EGR valve...
we took it apart, the seal cup was the hardest part as it's "punched" so we had to "cut" it, we discovered the ****ty seal in the shaft is a rubber oring which was completely eroded and the bushing also had plenty of play.
So we took it to a machine shop and made them do a sintered bronze bushing with far better tolerance, a special hi-temp seal and the cup was soldered with TIG (as it's stainles steel...), we closed again the diaphragm housing and that's it, a fixed, IMPROVED EGR valve that will outlast the engine itself.
We also bought new high temp orings(for the asv to egr to intake) as the original ones are flattened by the heat of the engine (bought them at an oring factory), greased with hi-temp lithium grease as well for better sealing.
Afgter all that, the engine ran less rough, fuel economy increased veeeeeeeeeery little(like 0.1~2 km per l)
It's not for the faint of heart and if you don't have a friendly machine shop/lathe guy you're toast...
