I've got hold of a couple of old TDV6 EGR valves (thanks to Disco_Mikey) to strip down and work out what goes wrong with them, and thought some of you might find pictures interesting. There's plenty of discussion on here about EGRs failing, so these pictures might help to illustrate exactly what it is that is being talked about
Of the 2 valves I have, one is definitely u/s caused by a seized motor, but the other appears to function OK. I only stripped the duff one down so far:
Both valves, one for each bank of cylinders:
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Valve in the closed position (exhaust side):
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Open:
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Exhaust gases flow from right to left when the valve is open (a pipe connect the port on the left to the throttle valve assembly/inlet manifold):
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Unless there's a blank fitted!:
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The 3 parts (position sensor, actuator/motor, aluminium valve body). Note the actuator should be the other way round
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This jaw on the actuator couples with the spindle seen in the back of the valve assembly, and rotates about 90 degrees to open and shut the valve:
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The valve opens and closes due to these guides in the valve body - the small rollers have ball bearings:
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but this valve had lost the roller on one side (the outer ring has broken and the balls were gone):
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This is the back of the actuator/motor, which appears to have suffered water ingress and corrosion (it was almost seized solid):
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Valve position sensor, which is a variable resistor to feedback to the Engine Control Module:
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Connector (pins 3 and 4 are for the actuator. 1,2 and 6 are for position feedback):
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Although both of these valves had some carbon build up around the valve ports it doesn't look like that is the reason for failure - the spindle moves freely and the valve seals well on the seat. I don't know the mileage that these had covered, but it would seem the weak point in the design is the actuator/motor which can corrode, and the valve guide rollers which collapse. I know this is only from stripping one sample, so hardly scientific, but it's a start! I'll strip the working one down later and see what condition that's in.Previously:
2005 D3 2.7 TDV6 S
1984 90 2.25 Petrol CSW
1992 90 200TDi Hard Top
1995 Discovery ES 300TDi
2003 90 TD5 Truck Cab
Had mine changed last week after 53000 miles.
Didn't bother to ask what had actually failed on the unit.
From what I understand they send warranty failed parts back to Land Rover for analysis.
The idea of the bearing collapsing and the bits finding their way into your engine or turbo sounds a bit !
22nd Jan 2009 10:23 am
character
Member Since: 31 Dec 2007
Location: wiltshire
Posts: 5781
hey mods can we have this as a "stickey" please
22nd Jan 2009 10:25 am
PaulP
Member Since: 04 May 2007
Location: Barcelona
Posts: 4317
Fantastic post RBM.....
I've always wondered what one of these really looks like in bits and know I know - thank you!
Rather than just a sticky, this is the kind of post that should go into the Wiki 2006 Discovery 3 TDV6 SE AutoBuckingham Blue 2007 Golf GT DSG
22nd Jan 2009 10:40 am
SJR
Member Since: 09 Aug 2006
Location: East Manchester
Posts: 4030
Top Work RBM
I think seeing one broken down like that would give me the confidence to take mine out and clean it if it causes problems in the future.
Had mine changed last week after 53000 miles.
Didn't bother to ask what had actually failed on the unit.
From what I understand they send warranty failed parts back to Land Rover for analysis.
The idea of the bearing collapsing and the bits finding their way into your engine or turbo sounds a bit !
All the bearing and roller parts were contained in the area between the valve body and actuator , so no chance of them going into the engine fortunately
I'll let you know what I find with the other (apparently working) one soon.Previously:
2005 D3 2.7 TDV6 S
1984 90 2.25 Petrol CSW
1992 90 200TDi Hard Top
1995 Discovery ES 300TDi
2003 90 TD5 Truck Cab
All the bearing and roller parts were contained in the area between the valve body and actuator , so no chance of them going into the engine fortunately
Oh Yeah. Just looked again!
22nd Jan 2009 11:22 am
discoBizz
Member Since: 20 Sep 2008
Location: Manchester
Posts: 1416
Nice-one ridgeback!!
So do these fail after a given number of miles or is it an imperfect part that could go at any time?
Definitely a wiki post me thinks
22nd Jan 2009 11:26 am
10forcash
Member Since: 09 Jun 2005
Location: Ubique
Posts: 16534
Quote:
One report from supplier confirms stem seal failure resulting in contamination
on control mechanism. ***** have confirmed they have caused seal damage in their production process which
has resulted in exhaust gases causing corrosion
That would explain the crud in the area at the back of the valve body, which probably caused the roller failure.Previously:
2005 D3 2.7 TDV6 S
1984 90 2.25 Petrol CSW
1992 90 200TDi Hard Top
1995 Discovery ES 300TDi
2003 90 TD5 Truck Cab
22nd Jan 2009 11:37 am
heine
Member Since: 07 Feb 2007
Location: Midrand
Posts: 4054
Definite Wiki candidate
22nd Jan 2009 1:41 pm
stapldm
Member Since: 11 Sep 2006
Location: Swine Town
Posts: 2330
Excellent work that man genius! I always assumed the valves were CAN driven, but that looks like a simple servo setup. As you've gone so far, any chance of some data for the resistance at various stages of open/closed and which pins attach to what?
No idea what that could be used for yet, but it'd be a shame to miss the opportunity 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."
Transgenic tomato anyone?
22nd Jan 2009 5:02 pm
London Lad
Member Since: 27 May 2008
Location: Suffolk
Posts: 505
Just a thought.....
If you had a working valve and you cut the prongs of the actuator and put it all back together with the valve closed (or blanked) then the actuator would work the feedback resister and the system would think the the valve was opening and closing when it wasn't really. ????.
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You should never argue with idiots because they will just drag you down to their level....then beat you with experience !
22nd Jan 2009 5:20 pm
Gareth Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26772
Same theory as blanking LL, only its easier just to fit a blanking plate if needed.
stapldm - I'll have a look tomorrow and see what we can get from the good one I've not butchered yet I'm not sure if the valve is just open or shut because if you apply 12v to the actuator it opens all the way. I suppose the ECM may pulse it to open or shut in small increments. Maybe one of the engine tuners (TFC, Bell etc) can help out with that question?
LondonLad - you could do that but you'd need to remove the valve to do it which is tricky. It's a lot easier just to blank it, then it doesn't matter what the valve does edit - Gareth got there 1st Previously:
2005 D3 2.7 TDV6 S
1984 90 2.25 Petrol CSW
1992 90 200TDi Hard Top
1995 Discovery ES 300TDi
2003 90 TD5 Truck Cab
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