Here is what I found :
EGR VALVE - what is it??? - SEAT Cupra.net - the world's largest & most popular SEAT Forum
Originally Posted by ralph
I thought you would get less smoke by removing the egr after all you will be getting a cylinder full of air as opposed to one diluted with exhaust gas. On a more scary note honest John said Renault suffer from premature turbo failure because the egr valve fails and the exhaust gas temp goes to high thus damaging the turbo. I am not sure I believe that though because egr's are usually closed at full throttle so it should make no difference. Anyone know anymore because I have two turbodiesels both running with no egr.
And then Tom B reply:
Originally Posted by ralph
honest John said Renault suffer from premature turbo failure because the egr valve fails and the exhaust gas temp goes to high thus damaging the turbo.
Honest John gets his info from a big liar then!
Renault turbos are breaking (note: not failing) because the ECUs are overboosting them, putting a nice hole in one of the impeller fins.
Result: lots and lots of loud whistling and a loss of power.
I did hear the same story about Renault DCIs.
That they put turbos in their engines almost to the max by utilizing maps that pushes turbo over the edge.
And that this is real reason for turbos failing.
I even found some long term testing of Laguna couple years ago where turbo blow off after 60000 km.
And then I found on Parker's forum:
Parker's forum - Renault dCi Turbo Problems. Read TOPIC l First!
IMPORTANT UPDATE 23/09/05
Apparently Renault UK is now making contributory payments of up to 100% to owners whose 1.9dCi engined cars meet certain criteria where the Garrett turbo has blown up. These contributions come via a "Yellow OTS Scheme" but it is possible that only French "reconditioned" turbo units will be fitted.
And this is the result.
Car manufacturer is paying something !!!!????
Admitting that something is their fault!!!
And after reading a lot more (it is a lot more than above) I can only say that Renault tried to mask problem with turbos and engine design by blaming faulty EGRs.
BUT, and there is always some BUT
But Garrett did not let French spit on their turbos as main source of problem neither the manufacturers of EGR valves (Pierburg and others) accept the blame.
And they have some figures that proves by statistic that fallen EGR CAN NOT affect operation of turbo charger.
Garrett agree with that AND Renault must admit that design (read as: ECU map) is not OK.
On Vag TDI and Pug HDI forums and also CRD forums in America (in Chrysler's Jeep and Dodge) almost everyone suggest closing EGR valve.
Also on Ford trucks 6.0 L Turbo diesels people even make and sell DIY KIT for blanking EGR off....
I had EGR stuck open (no power at all) and official alfa service told me instantly: "your turbo is blown, you need to buy new or reconditioned one...we do not recomend reconditioned but...bla...bla...bla"
Then, I did EGR blanking on my 2002 2.4 JTD 150 hp and suddenly my engine works GREAT.
Without ANY problem.
It happened 10k ago.
My turbo is working last 10000 better than ever