Dumb diesel design or cant be helped? Which? - davidh
As most modern CR diesel owners know, the EGR valve will eventually soot up one way or another, leading to the valve sticking. This requires either a jolly good cleaning of the valve or replacing it to the tune of about £125 depending on wether its salvageable (these valves can corrode internally so siezing the mechanism)

Symptoms of a sricking open valvle are (among others) usually low power at low revs - feels like turbo lag.

My questions are thus:-

1) Should EGR valve cleaning be considered routine maintenance?
2) If the inlet manifolds of a diesel car had exhaust soot running through it, is it only a matter of time before things like swirl flaps choke up? The GM/FIAT 1.9 diesel is known to have swirl flap issues.
3) Are design engineers hamstrung by cost / emissions legislations such that its a good idea to have exhaust soot whistling past (therfore collecting on) what look like delicate servo driven tumblers in the inlet manifold?

EGR valves are supposed to reduce NOx. I fancy blanking mine off to prevent the inlet manifold from choking up, would it A) Be illegal B) Fail an MOT - how would they know anyway? or C) Be morally reprehensible from an emissions point of view?

Dumb diesel design or cant be helped? Which? - brum
1) It would be too expensive to consider it routine maintenance

2) I am not allow to publish my views about GM/FIAT diesels under the forum rules.

3) Design engineers are human and make stupid decisions.....quite often.

A) Any modification from the certified deign/build is illegal under EU law (inc remaps/tuning boxes), however its never been known to be enforced. UK law is still struggling with the term "trafficator" ;)

B) At the moment there the MOT test does not test for NOx, but it may do in the future. If a tester caught sight of an obvious modification, he may be at liberty to fail or make an advisory, but I think it unlikely

C) Yes. Also all aftermarket remaps/tuning boxes should be banned.
Dumb diesel design or cant be helped? Which? - Altea Ego
1) If you do your own servicing, yes
2) GM/FIAT CR Diesels are no worse than any others.
3) It seemed like a good idea at the time,

A) In the UK - No
B) No
C) No