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· Registered
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Discussion Starter · #1 ·
Hi guys,

I am from South Africa and also has a 2011 BMW X5 35i (N55) which the other day something terrible happened.

As we were driving approx. 180kph down the highway we heard a weird (police siren) type noise then like a balloon deflating sound and all of a sudden we were covered in white smoke as we slowed down. I tried to drive on slowly (30kph) but then got a Engine oil low warning and immediately shut down the engine and had the car towed back to my company.

Car has no power and makes a metal clunking sound when moving it around with a lot of white smoke. It consumes oil at the rate of a heartbeat and the leak looks like its coming from where the exhaust connects to the engine / turbo...

Please help me identify this problem, read threads about PCV valve but wonder if its my turbo or complete engine that went?

In the meanwhile I'm driving my M50d but Im missing my petrol sound.
 

· Nuclear engineer
02/2012 X5 35d M57Y CPO 125+K miles NOKIAN WR G4
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24,581 Posts
Turbo seal or external joint may have failed, allowing crankcase contents to be expelled into/onto the exhaust system and subsequent un-lubricated rod bearing failure (the clunking sound). The siren sound being, perhaps, the turbo bearing failing at extremely high rotation speed.
 

· Nuclear engineer
02/2012 X5 35d M57Y CPO 125+K miles NOKIAN WR G4
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24,581 Posts
The only thing worse than a failed rod bearing is a thrown rod.

A friend's Sixties vintage AH threw a rod at speed and cut the block in half.
 

· Nuclear engineer
02/2012 X5 35d M57Y CPO 125+K miles NOKIAN WR G4
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24,581 Posts
Thanks a lot... But would the engine still be able to drive like it did if it was that bad?
Sure. It will clank until the rod end bearing support fails, the crankshaft will separate from the rod and contract the rod again at the next revolution in a random orientation.

Or it may not be the rod bearing making the noise at all. You takes your chances and THEN pays your money.
 

· Registered
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581 Posts
How much longer did you drive on it after the turbo went?

If it was more than probably 10-15 seconds, then you likely did starve some bearings of oil and that's the knocking sound.

I don't get why you'd try to continue to drive after something like that happens though...
 

· Nuclear engineer
02/2012 X5 35d M57Y CPO 125+K miles NOKIAN WR G4
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24,581 Posts
No breakdown lane on the freeway, wow?!

For the first few years while I had my TDI, every time I started it I went over the required actions for a runaway engine due to turbo seal failure, and for a failed timing belt. Both required stopping the engine as soon as possible and getting to the side of the road out of traffic. I'll the let recovery vehicle get me off the freeway.

The turbo turns up to 100K rpm at about 500°C and uses engine oil for cooling and lubrication. Yeah, the turbo probably - from 20,000 miles away - failed.
 

· Nuclear engineer
02/2012 X5 35d M57Y CPO 125+K miles NOKIAN WR G4
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24,581 Posts
The clanking is the everything else damaged. It is likely that the catalytic converters have been poisoned if they were wetted with lube oil.
 

· Nuclear engineer
02/2012 X5 35d M57Y CPO 125+K miles NOKIAN WR G4
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24,581 Posts
No. Worst case is short block rebuild for scored crankshaft journal.
 

· Resident Curmudgeon
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WOW. Some blindly hopeful and bad thinking by the OP and perhaps ill concieved advice in this thread/

IMO worse case, AND MOST LIKELY CASE, your motor is done.

This doesnt sound like a 'bad turbo'...at all.

Nobody- NOBODY- can accurately tell you what happened based on the description. but..you cannot consume 'quarts of oil' in seconds due to a bad turbo. IMO you have a catastrophic internal failure allowing coolant/oil to enter the combustion chamber. Engine likely toast.

Driving it for seconds after the event ensured it was gone, even if the initial event would have been survivable. Ive had motor issues before- eyes to gauges, clutch in while hand goes to ignition, off, coast to side of road. Period.

Get it to a qualified shop. Don't start if again.
 

· Registered
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581 Posts
WOW. Some blindly hopeful and bad thinking by the OP and perhaps ill concieved advice in this thread/

IMO worse case, AND MOST LIKELY CASE, your motor is done.

This doesnt sound like a 'bad turbo'...at all.

Nobody- NOBODY- can accurately tell you what happened based on the description. but..you cannot consume 'quarts of oil' in seconds due to a bad turbo. IMO you have a catastrophic internal failure allowing coolant/oil to enter the combustion chamber. Engine likely toast.

Driving it for seconds after the event ensured it was gone, even if the initial event would have been survivable. Ive had motor issues before- eyes to gauges, clutch in while hand goes to ignition, off, coast to side of road. Period.

Get it to a qualified shop. Don't start if again.
Don't agree with the above concerning turbos.

If you have a turbo shaft bearing go out, it will take out the CHRA (center housing rotational assembly) oil seals, which will dump out quite a lot of oil in a short period of time. It probably went both into the intake and exhaust, hence the white smoke. Basically ~100 psi oil squirting through a ~1.5 mm ID oil restrictor for a journal bearing turbo. It'll empty the crankcase in less than a minute I'd say.

And our small turbos spin about 150-180k RPM at peak power, pretty impressive when you consider how long they last...

But I do agree the engine is likely toast. Very few clattering noises that follow lots of oil smoke are good things for an engine.
 

· Resident Curmudgeon
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27,487 Posts
I'll stand corrected.

Still think OP is hosed, and this isnt a 'fix the turbo and you are good to go" story. (Which I think we are in agreement on...)

OP, post back when you find out more.... GL!
 
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