Although the turbo oil seals going can cause this that wouldn't tie up with the oil level being over 2" over the upper level on the dipstick. It's more likely that the sump has been over filled on the last service and the oil is blowing by the pistons causing uncontrollable combustion. I have read about quickfit doing this and blowing a VW TDI engine up while it was still on the ramp in the workshop.

 

how can the engine rev so much with the throttle closed?

 

I always carry the tools i need incase this happens along with an old coat that i can try to block the air intake with should it happen, scarey stuff but this isnt just a BMW thing it can happen with any turbo car.

 

Because the engine runs on engine oil!

 

diesels have no throttle plate, and when you switch off the key it just closes the fuel valve and thats how it stops, if the turbo seal is blowing by it will rev to its kinematic limit and stay there until if runs out of engine oil. best way to kill a runaway diesel is put it high gear, hold the brakes and let out the clutch. if you have an automatic you're screwed unless you can yank off an air hose and block it off with a board or something flat. happened to my friends ford diesel truck. we used a bottle from the side of the road and shoved that into the air pipe. saved the engine thankfully.

 

I would like to add, that the car was serviced properly. The mechanic is well versed and equipped and is definitely not a back street garage. I had done over 1000 more miles after service due and was about to get it in for Service- so it was not a matter of the oil overfilled.

Somehow- the oil level increased by two inches over the maximum line and it is not water. The oil does not smell of diesel but I am suspicious. I fill all the cars at the same station. I have read that if Diesel contains more than 5% of Bio-diesel in it, the fuel will dilute the oil. That would mean that the oil level would increase.
I have just a hunch - That bio-diesel was being added to the Diesel by the pump. My next step is asking a laboratory to check the fuel in my tank. I do fill my 525D roughly every week from near empty, so I do burn a tank`s fuel each week. That is quite a lot of fuel and enough for this to happen. I know that is criminal and would get the station to loose the licence if this is the case.

The engine has now a slight noise and I hope its nothing serious. My mechanic was a bit busy and could not have a deep look. He said that first he is taking away some oil to bring the level right and then start it up to check if something has been damaged and then try to determine what went wrong.

He said that the increase came from the fuel definitely and he will try to establish in what way could this happen. This is what I wish to ask forum members. IN what way could fuel find its way in the oil sump?

 

dats bosshaaawg!! :0

 

There is a similar problem with the Fiat 1.3 multijet diesel.

During the particulates filter regeneration, extra diesel is used to run the engine hotter and regenerate the filter, if this goes wrong you end up with unburned diesel getting past the piston seals and into the sump.

The sump level rises until it gets to the point where the oil pump pressure forces oil into the engine, it runs on oil and destroys itself if you do not manage to stop it.

http://www.telegraph.co.uk/motoring/caradv...ntrollably.html

 

apparently- I have read that BMW`s 5 Series have a DPF which is a Diesel Particulate Filter...
see this link....
http://uk.cars.yahoo.com/car-reviews/car-a...0d-1004084.html

the guy who posted the previous post indicated a link and this said that when this filter gets clogged, diesel would go into the sump oil.
I will post my findings here.

 

Hello again!
I funally have the casualty list
The mechanic has finally started to look at it. Removed head and there we were. One piston lower than the others.
when all is dismantled, we noticed the piston has a bent connecting rod. Two cylinder liners have slight marks and
a professional reborer said the marks will go off with honing.
There is too much play in the other gudgeon pins/connecting rods. The bent one looks with more clearance.
Several oil control rings look siezed.
The mechanic has suggested changing all pistons and con rods.
I have talked to a company in Italy running a hitech fuel testing facility and they said that the problem of oil increase is to do with the injectors altough my mechanic suggests checking the injection pump main spindle seal for leaks. They say that this is the culprit.
However, yesterday i was speaking with a mechanic and he asked me if I used to experience any white smoke at start up and I never did. He said that if it was the case that injectors were leaking that much diesel to incraese the level by two inches in about 3000 miles, if it was the case, I WOULD HAVE noticed white smoke when starting off in the morning. something I never did!
And the siezed oil control rings on the pistons I am told could be the cause after the incident, but I am starting to believe that the problem was actually the control rings on the pistons.....
what do you guys think?