Thanks.
still no ideea why even a new solenoid may work…. Randomly.

 

First of all…. Being the first message this year, happy new year and all the good things to you

secondly… I need some help. I was reading the manual today about turbo system and how they work , and there is an interesting passage for the secondary turbo. It said this…..If the engine idles for more than 3 minutes, the secondary turbocharger is actuated to ensure correct lubrication. This is achieved by pressurizing the turbine shaft bearing cavities through a pipe, which is connected to the air intake system and periodically opening the turbine shut-off valve to operate the turbocharger.
So….. pressurizing the turbo shaft bearings, where my problem is and leaking oil. Not enough to affect the oil level, not enough to go in limp mode, but enough to give me dpf yellow and to see drops on the flange in the hot side to the exhaust and 2 bottle caps of oil in the cold side . ALWAYS , I had the impression that it’s a iddle leak, because even on the hot side, it’s not burning, it’s not getting brown, those drops of oil at the connection towards exhaust. But….. those oil drops appear also at the next pipe connection in the exhaust, think after the dpf or just in front.

so…… how the pressurizing is done? From what? What pipe? From the air intake….. but how where and how again….???????? Maybe this is the reason my turbo is leaking. Not big quantities, no oil level dipping, but it does and goes into both sides of the turbo.

If anyone knows, please help. Any schematic, pictures, part numbers, ideas, ……. Anything is of help.
this is the picture from them manual.

 

Hi.
Happy new year for you too.

There are slight misprint on this or misleading. Oil pressure is always there. No control actuator on oil piping.
This means that secondary turbo is rotated during idle to keep oil not escaping to the turbine cabinets. Rotating keep axle sealing working.
The turbo-shut off valve is used for this function by letting small airflow to the turbine.
Turbo-shut off valve is the black solenoid sitting on the Turbo divider assembly (you called this front egr, what it´s not. No exhaust there at all). Primary purpose of turbo shut-off valve is to release boost pressure when you lift the pedal and boost is not needed anymore, and/or release boost pressure if its too high.

I can see two possibilitys:
- Your primary turbo is sticking and not rotating with small airflow at all.
- Your turbo shut-off valve do not work or sticking (or if somebody have made an tune on ECU and turn the function off)

 

great answer….. but i dont think this is the case.
look
f


From the pics you can se that from the turbo body there goes a 3rd metal pipe. Not the oil intake, not the oil drain. A 20 cm metal slim pipe, that is tied to another pipe with a ruber 5 cm conection…. So….. for sure it’s not oil feed. That pipe goes to the intake…. In the air box I think between the intercooler and the intake manifolds. Where…. There is….. boost. From the turbos and the intercooler. Boost that thru that pipe…. Goes to the….. turbo. Secondary one. So…….. as boost gets higher in the air box…. This pipe gets boost without any solenoid or control. And sends it to the…. Secondary turbo…. Exactly elegant it s needed…. Under boost building for secondary turbo spooling .

any ideas?
am I right?

and …. If the pressure pipe is blocked….. no pressure for the turbo bearings to keep the oil inside.
so….. it’s not about the oil pressure ….. that line, it’s about the air pressure to pressure the oil inside the turbo, as it gets to building boost

 

Hi,

Intresting.
The x351 service and repair manual do not mention these pipes ...
Not in Fuel charging - (from pages 124 onward) or Intake Air Distribution and Filtering (from page 141)
Can you follow where the pipe connect to the boost side of air intake? On the part what is connected by the circle clip to the throtle house? (there are one pipe right next to the temp sensor - never got the reason of that pipe )

 

from what i could find in pics…. Because it’s minus 10 here and the care is under cover…. That pipe gets in the air box just before the v split on the engine
meaning…. Here

just before the v. The black box that gets air directly from the intercooler.

my point being…. If that is what I think it is…. From the v split to the banks, lower…. It’s the egr pipes…. And just lower than that…5-10 cm it’s the box. If the air throttle actuator was stuck and replaced exactly because of soot from the egr that restricted the movement….. a to big restriction could go even Back… 10 cm to that air box and…. Block the air pipe, that is small…. That gives air pressure to pressure the turbo oil chambers. So…. No air pressure as per manual…. So…. Turbo leaks. And NOBODY took that into consideration. And I mean….. nobody. Mechanics….. techs….. the lor.
so…. Thoughts?

 

more than that…. Every picture… for every turbo or turbo core …. Has 3 holes. One oil intake from the back…. One drain down…. And this that leads to the front of the engine. And this…. Because the pressure is increasing with the rpm and the boost…. As the oil pressure in the turbo…. It gues it can get to about 2 bar…. That’s why it’s metal. And screw ed into the turbo core.
more than that. It has about 7..8 corners on the pipe. A lot of places to get kinked….. and not get corect shape again. Even if it’s not blocked from the soot in the air box. It’s a vicious circle…. Crooked pipe…. Oil in the egr and intercooler and air intake…. That blocks the pipe again….

So…. Simple check with a endoscope camera to see the route…. Or blow into it…. Or use a vacuum pump to se if it hold or not… the pipe has a conection close to the front of the turbo…. Where it’s joined by a thick rubber connection of about 5 cm to the short one that’s getting out of the turbo…. As seen in pics

 

Yes. No joy to work outside with the car at this weather. (We have around -20C here).
About boost control on idle: There are no boost. Inlet manifold is in vacuum side on idle.
My one defently don´t have any other pipes on throtle body, where the actual Y are, exept ones from EGR:s.
But the "airbox" before throtle body have one black plastic pipe, with twin finger operated "hooks" to keep it secured, right next to the input air temp sensor.
On the pic from top of the engine you add: Black plastic pipe turning 90 degree left and dissappearing left side of engine. I have been thought that this is the pipe used to create an airflow by engine vacuum (on idle) to make secondary turbo rotating. Because turbo divider valve is closed, the replacement airflow is made by opening turbo shutt-off solenoid letting air in so airflow can rotate turbo?
However: this is not clearly decripted and i never actually seeked it out when i have had any 3.0litre AJD-V6 on bench. (2.7 litre version don´t have this system at all)
To check if this pipe is free, would need to disconnect it both sides and push compressed air thru.

 

great answer and Info
but under boost….the “airbox” gets boost from the intercooler and turbos. So…. Under acceleration , might help the turbo with some pressure to keep the oil in the turbo. As described in the manual. That’s my logic.
yes…. In order to properly verify… need to disconnect both ends of the pipe. To see if clogged. But a good intermediary check is to put negative pressure to se if it has leaks.

I really hope that’s my problem with turbos leaking….. and this may help a lot of others. Will follow up with progress, after I make progress

 

Yes. You could add an pipe on and try vacuum it to see if its leaks?
Please report your findings.
Overall: These turbos are very reliable. Not many failures reported, so it could be that your original issue were not in turbos after all.

 

so….. for all who are interested.
I checked the pipe from the airbox on the engine , just before the air throttle in front of the egr recirculating system……. And…. YES, it comes from the turbo, or it goes from the turbo.

and after 10 cm it goes into that metal pipe all the way to the turbo


mine, was broken and patched with a fuel plastic hose, as you can see in the pics. It should be thin and hard plastic, not a piece of hose



and that plastic hose links the airbox jack to the piece of plastic left on the metal pipe.
with no clamp on the metal part. SO….. it had oily contact surfaces on the hose pipe and the plastic broken part, like it leaks a bit of air through there.

according to google…. Air box pressure is between 10 and 30 psi , meaning 0.7 to 2.4 bar. That means that pipe to the turbo might see pressure upward of 1…..maybe 1,5 bar. So , any pressure loss means no air pressure to the turbo like the manual said, meaning a leaking turbo.

My ONLY QUESTION at this moment is….. what’s the behavior of the air at the end, in the turbo.
does it just pressurize the turbo and stays like that, or it’s mean for the air to exit around the turbo bearings and axes, like the oil does at this moment on both sides of the turbo? Lets take under consideration, that the air pressure has to beat the oil pressure in the turbo , so it can keep the oil inside.

opinions? Constant pressure from the air in the turbo axes and bearings , or a flow of constant air that keeps the oil pressure inside the oil channel?

any experienced ideas are welcome!!!!!!!!!!

for me this info is necessary because if only pressurizes the turbo, I can check at this moment if it holds pressure via vacuum hand pump, but that also doesn’t mean that the pipe might be blocked bulky oily gases build up in time or soot from a clogged air throttle.
if the turbo lets air out , and the air flow and pressure from air admission is constant and pass through the bearings by design, that means that if it holds negative pressure, the pipe is clogged…… so no air pressure on the turbo bearings so leaky turbo

 

The joint defently should have clamp on it.
I am surprised thats the area are not oily at all, so it seems it have been holding?
No idea how turbo is using that pipe. I have been thought that this is used as vacuum line to make secondary turbo rotating on extended idling.

 

the manual is clear…. Pressurization for the turbo. To keep the oil in. The question is….. it should leak air at the turbo shaft and bearings or just hold air pressure? I am betting on a constant stream of air, to the turbo, a flow that exits by the turbo shaft. So….. should not hold negative pressure unless is clogged.
If someone knows….. or who knows some tech guys at the dealership, …… to enlighten us…..

meanwhile…… I will test different scenarios.
turbo holding air pressure from the pipe and ….. air getting out from the turbo axel.

just melted some small hose to fit that pipe to properly test the vacuum pump on the pipe.

Will do follow ups.

 

Note: On idle, when activitation of secondary turbo is planned to work, this air hose have an negative pressure. -> Primary turbo is not generating boost in idle rpm so engine is working as negative air pressure on intake system.
There should be an ECM controlled actuator somewhere on the piping activating this system after 3min idling. Maybe this actuator have another piping issue on your case?

 

you refer to the front air duct splitter. Yeah…. I changed that electrical one and also the vacuum one. And the solenoid. The the question is about the thin air pipe that goes from the air box just in front on the air throttle on the engine. That small one that feeds air to the turbo core. To pressurize the oil in the core .

 

Exactly: By description this happens after 3min of idling. So it must be somehow controlled.

 

it’s not about that. This pipe is feed directly from the air box in front of the air throttle. That means it has air all the time. No conection with the turbo splitter under the front car. This pipe directly FEEDS air into the turbo CORE all the time, in to the turbo core chambers. Yes, pressure varies from iddle at atmospheric pressure to 1,5…. Plus bar in full throttle.

 

Went and idled my car today after work and listened whats happens after 3min idle: Yes. The tone of engine changes about 3min mark. Not so much noticed on engine bay, but on exhaust ends well notiseble. It turns more rumbling. It was cold day (-16C) so i did not made more tests like try to release that pipe on idling or checking if boost pressure solenoid operates.
Now i really want to cut one secondary turbo half and follow up how the pipe effects on turbo
Need to check if any found on local breakers yard.

 

yesssssss….. please…. Do that if you can. After 3 min the tone changes. Electronic valve in front , between intercooler and motor opens, and air is sent to rotate the turbo core, to circulate oil.
but…..
the air pipe from the ai box is working permanently.
the question being…. Does the turbo core lets air out instead of oil at the ends, because of that air pipe from the intake or…… turbo core gets air and holds pressure…. For the oil in the core and around the turbo shaft

my opinion….. turbo core lets air out back and front, so in doing that it keeps oil inside the core and around the ax of the turbo.
like I said, my checking with vacuum hand pump showed that does not keep vacuum, but,,,,, it’s not dropping directly….. trues to keep air . I have to check still the rubber pipe that joins the short pipe on the turbo with the long one that goes on the engine

 

PS: I have looked at houndreds of turbo pics. Second hand. ALLL….. I mean ALLLlLl….. have a leak on secondary turbo. Guess it’s not a turbo problem, it’s an air to the turbo axel problem. Broken pipe, pipe screw not good or holding, rubber part pipe not good….. pressure from the air box gone,……. Or blocked pipe by gas and oil in the air box