Looking for some thoughts on this. Does this plenum look split? I can get my fingernail in the gap but not 100% sure it’s actually split or not. Let me know your thoughts.

Have you cleaned it ?
It will have traces of black oily soot if it is split.
Wipe around the seam with a piece of white tissue or kitchen roll.
Mike. G reg 2.5VM Vogue Portofino red 1991- 1999
V reg 2.5td P38 Rioja red 1999- 2006
53 reg td6 Vogue Oslo blue 2006- 2015
11 reg 4.4 TdV8 Vogue SE. Baltic blue 2015- date.
https://www.fullfatrr.com/forum/topic56162...tty+affair

Hi Mike, it had a misting of oil prior to me wiping it down and the misting leaves a deposit on the oil filter cover which I would expect if air was being blown out if the seam 2011 TDV8 Vogue SE

High pressure smoke test is the only way to be 100% sure, but I suspect it is split from your reply.
When I was compiling the 4.4 tdV8 fault log, several were reported to have failed , always splits along the seam.
Mike. G reg 2.5VM Vogue Portofino red 1991- 1999
V reg 2.5td P38 Rioja red 1999- 2006
53 reg td6 Vogue Oslo blue 2006- 2015
11 reg 4.4 TdV8 Vogue SE. Baltic blue 2015- date.
https://www.fullfatrr.com/forum/topic56162...tty+affair

It would make sense Mike I think I have the one Range Rover that is plagued by all the faults currently on your list  2011 TDV8 Vogue SE

Might be one of the factors causing your issues....worth making sure  Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
2025MY Defender D350 90 in Silicon Silver on coils
1974 Series 3 Lightweight = "Millie"
Many, many other Landies over the years
My preferred specialist: www.glenrands.co.uk
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Unfortunately its quite common... But at least its easy to replace unlike the 3.0

Craig - what symptoms would this issue cause? Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
2025MY Defender D350 90 in Silicon Silver on coils
1974 Series 3 Lightweight = "Millie"
Many, many other Landies over the years
My preferred specialist: www.glenrands.co.uk
--------------------------------------------------

Rob,
I logged several in the fault log and they all reported very similar symptoms to split hoses.
Restricted Performance under load was very common plus usual DPF soot filling up rapidly .

Mike. G reg 2.5VM Vogue Portofino red 1991- 1999
V reg 2.5td P38 Rioja red 1999- 2006
53 reg td6 Vogue Oslo blue 2006- 2015
11 reg 4.4 TdV8 Vogue SE. Baltic blue 2015- date.
https://www.fullfatrr.com/forum/topic56162...tty+affair

Mike answered it for me DrRob…

Many thanks for all the responses gents, much appreciated. I'll order up a new plenum and get that fitted hopefully this weekend. I did have a high pressure smoke test carried out some time ago (or at least that is what it was booked in for), no leaks were found during the test, however, the passenger side inlet manifold was replaced as they suspected it was cracked. 2011 TDV8 Vogue SE

Mine does not have that sort of split in it. Checked yesterday when cleaning MAP Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
2025MY Defender D350 90 in Silicon Silver on coils
1974 Series 3 Lightweight = "Millie"
Many, many other Landies over the years
My preferred specialist: www.glenrands.co.uk
--------------------------------------------------

Hi all. Had a split appear in mine , luckily on the top. Used a good quality epoxy resin to seal temporarily . It is still there and working months later . Must get that new plenum ordered.... ----------------
2010 RR tdv8 3.6 ( gone but not forgotten ...)
2012 RR tdv8 4.4
2004 RR 4.4 V8 (M62) -gone but not forgotten (sob)
1998 P38 RR - least said the better
2009 BMW 7 Series 3.0d
Various motor cycles - BMW GS
1998 Jag XKr 4.0 V8

@kij

If yours is holding then I would carry on with it until it decides to split again as you won’t get much change out of £500 if you want a new genuine replacement 2011 TDV8 Vogue SE