Any info regarding air changeover valve between turbos?
Had a restricted performance alert after 50mph section of Motorway when I put my foot down to overtake line of slow moving HGV's.
Clouds of blue smoke and no power.
Assistance man said valve stuck ??
Car now back with dealer (under warranty)

Does it have the updated secondary turbo drain fitted? If not then it may have been accumulating oil in the secondary inlet tract. A stuck change-over valve doesn't cause lots of smoke but will cause restricted performance.

No, I don't think the turbo drain mod has been done.
The assistance mechanic said also that later models (presumably) 405's have modified changeover valves.
Could it be a known problem?
I will be asking MD for more info.

do you drive mostly under 2000 rpm?

if so then that could account for the clouds of smoke from the secondary turbo, the oil builds up when you switch off, the pressure in the oil feed doesn't bleed off and pushes past the seals into the secondary turbo. only small amounts though. However if the turbo isn't spooled up regularly then the oil will build up and you get the smoke.

if the valve is stuck the a replacement will sort the reduced performance, Personally I'm holding off having the drain mod done as i don't fancy letting a LR tech drill into the engine. Have contented myself with spooling up the secondary turbo more often  There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2021 Discovery 5 D300 MHEV commercial

You will know 1500 RPM is over 80mph in D, so I will have to start manually selecting 4th gear to see how it goes?
I should have added in the original post, it only took the mech 40mins to free up the valve with a spray of WD40 or equivalent . He was then able to clear the restricted performance alarm and the car was running fine for the rest of my trip and again yesterday morning on a 30mile run to the dealers.

Don't need to run at 2500 all the time, but there is so much torque available that with a less than heavy foot its possible to never use the second turbo.

This is borne out if you look at the air filters, one for each turbo...... the one for the primary is invariably filthy whilst the one for the secondary is clean like its new.

It just needs to be spooled up once every couple of trips to clear the oil build up just kick it down a couple of gears during an overtake or hold a gear a bit longer when pulling off. Its possible to do this without using the paddles, or massively changing driving style.

I agree it shouldn't be how it works but it seems to keep the problem at bay. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2021 Discovery 5 D300 MHEV commercial

Thanks Nmj, I think you have explained the sequence , and put my mind at rest.
1) I rarely get to 2500 RPM.
2) I put my foot down hard to pass HGV's and exceeded 2500RPM. Hence second turbo kicked in and blew out possibly weeks of oil build up.
3) Because the air valve was stuck, Reduced Performance alarm tripped.

NB. Not very nice stuck in outside lane in clouds of blue smoke with HGV's passing in lane 1 & 2.

66 yrs old and will have to learn to drive differently !!!!

Are you able to post the whole LTB?

Edit: Having checked my MY12's valve I can see that it does not have the nut so the TSB is now of no interest to me.

Forgive my ignorance but is a stuck change over valve as a result of the oil drain pipe issue or separate?

In essence NMJ is saying give the car a wack to clean out the secondary turbo but could this cause the stuck valve? I took advantage of a late night motorway run last night to go above 2500rpm and sure enough the old girl had a big fart out of the back but i do wonder if doing this can cause problems elsewhere?

I think its best to use the secondary turbo when no one else is around!!

I'm with NMJ on not letting LR drill holes in my engine!!  405 AB exec seats Baltic and Cirrus
93 RR Classic efi

Remember it's easier to get forgiveness than permission!

Gone in order:
4.4 TDV8 SE - gone to a good home
93 Classic hard dash Plymouth Blue
03 L322 Oslo Blue
2000 Disco TD5 ES Epsom Green
98 P38 Rioja Red
89 Classic Cairngorm Brown

2 loosely-coupled problems that can occur if the secondary turbo is rarely used. The oil accumulates from the unused turbo and the valve's linkage can become sticky from dirt/grit getting into the joint to the extent that it doesn't move freely if not used frequently enough.

2500+ rpm is not going to harm anything, just use more fuel.

I have been told that the modified operating arm moves much more as the 2nd turbo fires up .
It was the very small amount of movement in the original design coupled with infrequent use that causes it to stick.

Not got mine back yet. They have found a split turbo hose as per TB00523v2.
They have ordered parts for delivery Tuesday.

PS. Keep off the M62, Tuesday PM, blue smoke expected from Baltic Blue !!!!!