What sort of mileage has it done and what’s the oil change history like?


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50k serviced at bmw until 30k then independent up to date I’ve had it serviced by an independent every year regardless of mileage

 

Hmm so unless the car has been ragged its probably unlikely to be a completely knackered turbo but it would be worth getting an inspection done on it.

Usually its easy to check axial and radial endfloat of the compressor with your fingers ... there should be slight movement (the compressor spins on oil bearings so very slight axial and radial movement is normal), and it should spin up with your fingers easily without any noises. Anything more than very slight movement though is a cause for concern.

Also have a good look for cracks in the casing. I had a MG montego turbo years ago where the turbo rattled when it was cold but was fine once warm, on inspection it was a cracked casing that was catching on the impeller blades when cold but once warm the crack closed up. The rattle was characteristic though as it changed with engine load as the turbo started to spool up)

However, Im intrigued by the fault codes. From what I can see the oil system uses a configuration that should pump the correct volume and thus pressure based on the a characteristic map, i.e. throttle input, engine speed, torque requirement etc and this is controlled by a pressure control valve and measured by the oil pressure switch.

See this newtis article which shows the basic arrangement - not quite the same engine shown but the theory is much the same.

https://www.newtis.info/tisv2/a/en/e87-120i-sha/wiring-functional-info/power-train/engine-electronics-quality-control-valve-msv/engine-oil/Y4YOM3Z

So the pressure sensor is measuring the pressure it is expecting and faulting it because its higher than what its expecting for a given engine load. The control valve bleeds off excess pressure (for a given engine speed and load) and if that fault code is generated the valve will go into an emergency mode (unregulated full pressure I think). This could help oil get pushed past the turbo seals and although you cant see any oil when accelerating once you get up to speed the exhaust gets dissipated quickly in the air and unless its a terminal failure of the turbo you may not see anything whilst driving.

On balance I do think some form of turbo problem is the most likely - there shouldn’t be a rattle, but id still look into the oil pressure circuits and swap out the pressure sensor or control valve (whichever one is cheaper) to start to narrow down the oil pressure snag too, which may also not be helping the situation.


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Wow thanks for your reply !

I’ve just been out to check the turbo,
I haven’t taken all the heat shields off but having said that the lower part looks loose it may be that !!
Anyway I can’t see any visible cracks.
I took the air intake pipe off and inspected the impeller there is little or no end float and it spins nice and smoothly with no noise whatsoever.
So my next question is where is the oil pressure sensor located I’m guessing on the block somewhere ?
I think like you say start with the cheapest option first.
Many thanks for your help with this.

 

Wow thanks for your reply !

I’ve just been out to check the turbo,
I haven’t taken all the heat shields off but having said that the lower part looks loose it may be that !!
Anyway I can’t see any visible cracks.
I took the air intake pipe off and inspected the impeller there is little or no end float and it spins nice and smoothly with no noise whatsoever.
So my next question is where is the oil pressure sensor located I’m guessing on the block somewhere ?
I think like you say start with the cheapest option first.
Many thanks for your help with this.

I have same problem, so how you solved it? Did you change solenoid pressure valve or pressure sensor? Or both? Thanks.

 

The oil pressure sensor is at the rear of the oil filter housing and yes I would expect that to be the cheapest thing to try first.

The pressure control solenoid is attached to the oil pump which is inside the sump (the wire passes through the lower part of the block just above the sump to block bolts. You have to drop the sump to get to the control solenoid. Although there is mention of a solenoid repair kit (BMW doc reference 11 41 519) so I’m guessing these have been problematic. That looks like a nightmare job though so let’s hope it’s the pressure sensor !!!


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The oil pressure sensor is at the rear of the oil filter housing and yes I would expect that to be the cheapest thing to try first.

The pressure control solenoid is attached to the oil pump which is inside the sump (the wire passes through the lower part of the block just above the sump to block bolts. You have to drop the sump to get to the control solenoid. Although there is mention of a solenoid repair kit (BMW doc reference 11 41 519) so I’m guessing these have been problematic. That looks like a nightmare job though so let’s hope it’s the pressure sensor !!!


Yes let’s hope so ! Thanks so much for your help I will let you know the outcome.

 

did the sensor replacement work? got these two codes today….

 

I have same problem, so how you solved it? Did you change solenoid pressure valve or pressure sensor? Or both? Thanks.

 

J’ai le même! Résolu?