Really worried about this

This happened this morning, really worried I now have an engine problem. I have a 200 mile journey to do on Monday! The car was serviced at 17k miles, it’s now done 27k.

 

If you haven't already find the dipstick and check manually.

This can happen if the car has had too many aborted DPF regens. If the oil level was full, the car doesn't burn any oil and it keeps trying to regen some diesel slips past the piston rings and oil level rises.

I think the BMW fix is just to drain some oil out. What you really need to do is change the oil.

 

About 3 years ago I called in the Isuzu dealer [Warrington Commercials --fantastic dealership] with my sons DMax.

While in they decided to check the oils as they had a trouble with a similar truck. They then showed me the dipstick, which was way over full mark ,up to an "X" mark.

This indicated that fuel was getting into the engine. While I had coffee and bacon butty they changed oil and filters ( commented the oil and filter would have contaminated) ,and reprogrammed part of the ECU. Never occurred again,
but never found out why as the truck had been regen as frequent as ever -----it has a gauge that indicates the state of when the regen is required or occurring.

 

Well I did 375 miles in one day only a month ago, so it would have regenerated then? It is however mostly used for short journeys. It’s still within the three year manufacturers warranty so would they change the oil for free?

 

It's the lots of short journeys that are the problem. The car will keep attempting a regen until it's successful.

You can ask BMW to change the oil. They'll probably claim the fault is your driving style but I know two VW owners that have had EGRs replaced free of charge despite the reason they clogged being numerous short journeys.

 

But is it safe to drive for our long journey on Monday?

 

I'd look at the oil level on the dipstick, on the level, a few mins after the engine has stopped. If just a few mm over max, perhaps 5mm, I'd risk it. More or a lot more and I'd get some oil taken out - a full oil change could wait.

I think I've overfilled my 535d before, just a bit, and had no ill effects.

 

Sorry to hear that @kleynie. I just hope that it's something simple like a level sensor.

The comments regarding the possibility that it's due to fuel in the engine from failed regens, I find surprising. Although I don't know the details of how the DPF is regenerated, I had always assumed that the fuel is injected directly into the exhaust system somewhere rather than into the engine? But only an assumption of my own. I would have thought that any fuel injected into the combustion chamber would be burnt??

 

First check would be the dipstick Ian. I don't know if bmw would change it for free, as said above they might blame your driving style. I guess you might try to factor in a longer journey once every couple of weeks.

If it is indeed a rising oil level due to diesel getting into the sump then it will need to be changed. However as it is a lubricant then you should be fine for your trip on Monday, just don't put it off

 

@Mieke the extra fuel is injected into the cylinder during the exhaust stroke. Apparently if the dpf is blocked then unburnt diesel leaks back into the cylinder and into the sump. This is what I've heard however I retain a bit of skepticism about the exact mechanism of action.

 

There is an allowance for oil dilution, you need an idea of how much. As Jason suggests, check to see how much the overfill is reading on the dipstick. Then make a judgement on whether it appears a slight or severe dilution.

Oil dilution is typically DPF regeneration issues, but there is the less common risk it could be the HP fuel pump leaking diesel back to the sump.

Peter

 

As others have said I would check the actual dipstick. On my car the idrive shows at max yet the dipstick shows around midway between max and min..

If it shows high on the dipstick can you not get BMW emergency services to recover the car and get you into a hire car? Although I appreciate this is hassle you could do without!

 

Poor regeneration attempts definitely causes oil dilution.

Not wanting to scare 'anyone', one of my local garages who used to do recovery work, have seen some really diluted oil. One car, they drained double the quality of oil, than should have been in the sump. Another, the oil was so diluted it lost lubrication properties completely and put a rod through the side of the engine. One problem that is even more critical, you can have oil dilution and burn oil at the same time, there may be no visual sign of oil level rising.

It is essential to check what the real oil level is, before making a decision to drive any distance.

Peter

 

For me the dilution is a concern, and I'd definitely be changing the oil, but for a journey on Monday I'd be worried about too much oil bursting a seal somewhere.

Diesel is a very poor lubricant but the oil is degrading from the time it is put in so the car (and/or the oil) has to deal with its lubrication degrading between services. This manifests itself as engine wear over the life of the vehicle.

Back to the original post, if the oil level has truly increased then it is mostly likely diesel getting into the sump somehow, however oil level sensors are not 100% reliable either so it could be the sensor.

 

Difficult to call ES as I am on the train to the Lake District for the weekend, not back till Sunday eve and then a funeral in Margate on Monday in the car.

 

If I were you I would check the physical level on the dipstick when you get back as I think it is more likely a faulty sensor. If the level appears high drive the car home and get ES to it as soon as you can. Would the little Audi be up to the job for the Monday journey if needs be?
I know of several people with BMW's who have had faulty oil level sensors and I would guess it is most likely to be this especially the age of your car. Try to have a good weekend in the lakes - the weather should be glorious

 

Thanks. The Audi is in bits still otherwise that would have been a good shout. I’ll worry about it on Sunday evening when I return.

Thanks all

 

Could it be a leaking injector? Given your time constraints, I'd just hire a car for the day - dead cheap and well worth it for your peace of mind, in my opinion. Get yours seen to when the pressure's off.

Belt & braces, me.......

 

I’d favour a faulty sensors, allbeit support the short Journeys causing dilution...
I’d factor this into the much debated interim oil change discussions according to your driving style....
Being low mileage user, I’m a once a year type - circa 4/5000 miles per oil change

Regardless, hope all is well!

 

Had this once on mine as well recently. Checked the real dipstick, it was over the mark a bit. In my experience the electronic dipstick does tend to over-read a bit. Removed 0.5 litres and it was back to max on the real dipstick. (So if the overfill was all diesel and the oil was full before, I reckoned there was about a 7% dilution based on their being 7.2 litres total oil in the engine. Not bothered by 7%). Did nothing else other than keep an eye on it. Not moved since (touch wood).