Annabelle
Member Since: 27 Feb 2009
Location: Camb/Beds
Posts: 216
  
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| Why does carbon build up in the EGR valve? |
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Just picked up my 06 manual TDV6 from menders after having the EGR valve replaced. My question is as above, why does carbon build up? And is it something that does have to be replaced more often than not - I have got about 30 k on the clock but I have a friend who has an 07 with similar mileage and he has had 2 already replaced under warranty. I have an RAC warranty purchased at the same time as the vehicle through the Car Shop who are a load of "stunts" but thats another story, my warranty would not cover it!
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 12th Jan 2010 7:47 pm |
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Gareth
Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26702
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My last D3 did 130000 miles on the same egrs, no problems at all. And it was an early car!
My new one has done 30000 and so far no issues. I do drive them pretty hard, and that may have a bearing on the amount of carbon building up in the egr's and turbo.
(fingers crossed now  ) I have never had a turbo fail either. 
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| 12th Jan 2010 8:24 pm |
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Annabelle
Member Since: 27 Feb 2009
Location: Camb/Beds
Posts: 216
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Being a lady who likes ladies things, Gareth, my D3 has a very gentle life....I wonder if thrashing the "dangly bits" off it occasionally may be the answer?!
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| 12th Jan 2010 8:29 pm |
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stapldm
Member Since: 11 Sep 2006
Location: Swine Town
Posts: 2330
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I think giving it a good thrashing once a week should ensure that the turbo remains unclogged as well as blasting some heat at the EGRs. I know you have a manual, but it's also important in an Auto so that the kick-down mechanism and the galleries and pressure valves get a good flow going through them.
I seem to recall that you need revs above 2300 for the turbo to be working hard, so a shift down to a gear that gives you around 2200 to 2500 followed by hard acceleration (preferably up a decent hill) for at least 10 seconds should ensure the variable vanes get a full workout in the turbo.
Make sure your engine is 1) At running temp first 2) At the correct oil level 3) Has the timing belt replaced as per service schedules and 4) not taken past the 4000RPM redline during this.
I think that's right, can anyone please check my work and confirm? Dr. Ian Malcolm:
"Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should."
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| 12th Jan 2010 8:38 pm |
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NJSS
Member Since: 06 May 2009
Location: Catherington, Hampshire.
Posts: 10502
 
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I don't know whether this may also help EGRs.....my last Disco did 118k without any problems, but i (almost) always allowed the turbo to cool, usually for 60 seconds or so.
Quote:Because the turbocharger will heat when running, many recommend letting the engine idle for one to three minutes before shutting off the engine if the turbocharger was used shortly before stopping (most manufacturers specify a 10-second period of idling before switching off to ensure the turbocharger is running at its idle speed to prevent damage to the bearings when the oil supply is cut off). This lets the turbo rotating assembly cool from the lower exhaust gas temperatures, and ensures that oil is supplied to the turbocharger while the turbine housing and exhaust manifold are still very hot; otherwise coking of the lubricating oil trapped in the unit may occur when the heat soaks into the bearings, causing rapid bearing wear and failure when the car is restarted. Even small particles of burnt oil will accumulate and lead to choking the oil supply and failure. This problem is less pronounced in diesel engines, due to the lower exhaust temperatures and generally slower engine speeds.
Turbochargers can also suffer bearing damage and premature failure due to throttle blipping right before shutdown. This may cause the turbo to continue spinning after the engine has shutdown and oil pressure has dropped.
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| 12th Jan 2010 8:58 pm |
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Annabelle
Member Since: 27 Feb 2009
Location: Camb/Beds
Posts: 216
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That sounds very logical, Stap, it is interesting that quite a few D3s are run by "school run Mums" obviously doing a lot of short journeys that cause the carbon build up. Egrs dont have bearings in them so I am not sure that idling the engine would help.
Last edited by Annabelle on 12th Jan 2010 9:01 pm. Edited 1 time in total
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| 12th Jan 2010 8:58 pm |
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heine
Member Since: 07 Feb 2007
Location: Midrand
Posts: 4054
 
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When we all got together to block off our EGR's it was quite apparent that there was less carbon build-up in the cars whose drivers had a heavy foot. Mine had almost no build-up 
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| 12th Jan 2010 9:01 pm |
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Annabelle
Member Since: 27 Feb 2009
Location: Camb/Beds
Posts: 216
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Hmmm, note to self, drive more aggressively and ignore screams from children in back!
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| 12th Jan 2010 9:03 pm |
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Paganuk
Member Since: 23 Oct 2008
Location: Glos
Posts: 544
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| 12th Jan 2010 9:47 pm |
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Jonty
Member Since: 13 Oct 2007
Location: On the beach
Posts: 417
 
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Just get them removed!
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| 13th Jan 2010 2:53 am |
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Bushwanderer
Member Since: 27 Nov 2007
Location: Northern Rivers, NSW, Australia
Posts: 2050
 
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What, the kids?  The Bearded Dragon
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| 13th Jan 2010 4:23 am |
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heine
Member Since: 07 Feb 2007
Location: Midrand
Posts: 4054
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Annabelle wrote:Hmmm, note to self, drive more aggressively and ignore screams from children in back!
If you can hear them scream your radio isn't loud enough
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| 13th Jan 2010 9:44 am |
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C42
Member Since: 04 Apr 2009
Location: midlands
Posts: 10
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After having a visit from Land Rover recovery only yesterday for an unrelated issue (D3 failed to start on the way to the dealer to check out engine management warning light!), the service technician said the light was most likely caused by the EGR’s. His recommendation for the future was to give the car a bit of a thrash every now and again to get rid of the carbon build up on shorter journeys.
Hope this helps.
John
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| 13th Jan 2010 5:05 pm |
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DiscoDunc
Member Since: 08 May 2006
Location: Bristol
Posts: 16390
 
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ive done 106K in an 06 car and so far no egr problems - i assume that using it every day and for long journeys doesnt give the carbon chance to build up.
you need to drive it more  Duncan
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| 13th Jan 2010 5:14 pm |
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Baben
Member Since: 15 Feb 2006
Location: Kyalami
Posts: 2059
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regarding Heine's comment - I think he has a good point - my EGR's were filthy, and at that stage the vehicle had been used in the city for most of its life, with the occasional outing to the bush. Thrash it or remove it is my 2c worth.
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| 13th Jan 2010 5:18 pm |
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