Could a new/recon turbo still be leaking

[pochee]

Hi guys.
Hope someone will be able to give me some advice.
Sorry in advance for the long essay
My wife's X3 2.0d (e83) was diagnosed with a faulty turbo about a month or so ago. Long story short, the car was repaired for her, by one of our family members, but i am not sure the mech he took it to knows BMW's.
When the X3 was diagnosed, it was smoking alot, darkish plumes of smoke were coming from the exhaust, and the car was using a bit of oil (a pint every 1500Km or so)
Turbo was replaced, but the mech didn't change the oil. So I did an oil change when we got the car back. the car was still smoking a lot, I was told that the car needs to be driven so that the oil can burn out of the exhaust system/catalytic converter - Mech told the us not to decat it.
3000kms onwards, and the car is smoking worse than ever.
X is using more oil than i've ever used between services (2litres over the last 1000km)
It randomly looses boost, then when i drop down a few gears it slowly builds up boost pressure and the turbo slowly comes into life again, then it will be fine for a few kilometres, and then does the same thing again.
The turbo makes a grinding noise between 2500 and 3500 rpm after second gear (not sure if it is the turbo, but only when the turbo kicks in does it make that sound)

I took the car back to the mech, and he says that its probably one of the rings that have collapsed. I'm not so sure...
everything was fine before the turbo was replaced

Could all this still point to the Turbo being the issue, as i am not sure if he put a recon unit in, or if the turbo seal is leaking. Oh, and the exhaust developed a hole in it. Going to have it looked at when i have the courage to drive it again.

I am now scared to let the wife drive the car for fear of something else breaking, and it costing us another arm and leg.:blueCry:

 

[Major]

Mechanic sounds like an idiot. If turbo shat a seal and was leaking into the exhaust and cats, who knows what it looks like inside now. For all you know there's huge amounts of back-pressure now which is forcing weak-points to fail (seals for a second time, hole in the exhaust, etc). Put it on a flatbed and take it to someone who knows what they're doing. I wouldn't be surprised if there's all sorts of blockage in the exhaust, boost pipes, etc., things will get expensive quick.

 

[JayDrft]

Pochee,

I wouldnt stress too much.

It is most likely the thrust washers in your turbo that have gone. Which causes the impeller shaft to "float" if you could say that - which in turn starts affecting the seals and causing leaks.(Boost or Oil)

If you are not technically inclined - my suggestion would be to have someone check the condition of the engine first. Who knows what caused the turbo to give up in the first place. Was it oil starvation, dirt or debris that got into the turbo, driven hard, rapidly cooled(resulting in possible hair line cracks-on the exhaust housing).

You need to determine the cause, cause you may end up replacing 20 turbos, and the cause may be something else. Consider the mileage and frequency of services and it may tell you a story al by itself.

The symptoms that you described, are similar to the expereince that I have had on a custom turbo setup we have been having issues with. 5 brand new turbos later, and we determined the turbos were over working....increased the turbo size, and dropped boost - and boopla....running like a dream now.

I have a guys number that helped me with my setup...he has a wide range of good second hand high quality turbos and also new...but before you go that route...determine the following on the engine.

A simple compression test will indicate the state of seal in your bores aroud your piston - if compression test shows any deviation in cylinder pressures, it will indicate rings that have either collapsed or being bypassed.

Another thing to check, is oil pressure to the turbo. This coul dbe done with a temporary inline oil pressure guage, and you will also need to make sure that the oil is returning into the sump - to identify if the oil flows lik eit should through the turbo. In your case, its leaking oil via the seals into the exhaust housing. You could also check the intake to the motor to see if there is any oil coming from the compressor side(which I doubt).

These are fairly cost affective ways of diagnosing the car yourself....will save you Thousands...then at least you will know where you are headed, or have a better understanding of the root cause of this problem.

Just for peace of mind - I doubt the bmw diesel motors give up that easy...so my money is on a faulty turbo, either a cracked or worn exhaust housing or a poorly reconed turbo...

I hope this helps somewhat - if needed, I could offer my assistance where needs be, then I can refer you to a turbo guy that can actually assist you onto the road of recovery and confidence. Take note - the turbo guy that I am talking about, only works on turbos - no motor/engine work conducted(this is from experience where a customer will indicate its a turbo issue - when in actual fact,the motor has failed to support the turbo correctly for whatever mechanical reason and he ends up being blamed for the engine failure).

 

[pochee]

Thanks Major and JayDrft


@JayDrft, Thats not the first time someone has mentioned the impeller shaft to me. And also, I like your approach. Root cause analysis :clapper:
Think I'll take a day off from work to get the compression test done next week. And also check on the oil pressure as well as the flow of oil through the engine and turbo.

Once we find the issue (if any with the engine), I will give you a shout about seeing your turbo guy.

Another thing guys, Is there any reason i shouldn't decat the X3? (once the engine is properly diagnosed and repaired, of course)

 

[JayDrft]

Pochee,

Reason I am saying impeller shaft or thrust washers...I have had experience with the turbo popping on both housings - Compressor and exhaust side.

Popping on the exhaust side will dump oil out the exhaust, and it takes a while to burn out. Popping on the compressor housing side will cause a boost loss....From what you described, it seems to be doing both.

So just to give you a better understanding why the impeller shaft is mentioned...the centre core is where your oil is fed through...on either side it has seals, if for any reason you have a oil feed problem, over boost or any abnormal surge in the mechanics...its going to put strain on those thrust washers/seals...eventually the thrust washer looses tension due to being over worked, and it causes the impeller to "float" left and right, under acceleration and decelleration...at the same time, the impeller tends to touch the housings cause of the left/right float...so I can guarantee you, that once you open your old turbo up, you will see scuff marks on the respective housings, maybe more on one than the other. This is probably where you getting that grinding noise.

I hope I explained it well enough...thats my understanding of the dynamics inside a turbo.

Compression test is fairly easy and cheap to do....on a diesel a little more tricky, cause of the injectors....just another question - does the car battle to start...cause with my limited knowledge of diesels, it requires compression to combust...so if its battling to start, it may indicate a slight compression loss...if it starts easy, I doubt its a compression issue.

 

[pochee]

That explanation was excellent. I understand the very basics of how the turbo works, but that details was brilliant.

It starts easy, no issues. Have never had any issues with the starting, but I think just for peace of mind, i will take it through for some tests - it is after all the wife's daily drive.

I've been given guy to take it to here in the south of Jhb, apparently he comes highly recommended. Will go check him out for a second opinion (he comes highly recommended, only high end BMW's in his workshop), and if i am not mistaken, the current turbo is still under guarantee for the next 2 months.

Thanks again. Really appreciate the help.