Diesel in the engine oil

Question

So yesterday my skoda rapid 1,6tdi decided that she has had enough. Basically white/grey smoke started to blow all of a sudden and revving sound, really loud one. Somehow managed to idle all the way to a safe place. Recovery took to a nearest skoda garage. Now they had it overnight and on the next day they telling me that "engine oil overflow by 4ltrs" how the hell this has happened I really cant understand ,as I have serviced my car a year ago, and I do not do any adding to my car myself, only skoda dealers. They telling me that glow plug has gone too, one of them. Now I have looked online and looked for answers in here-apparently it's not overflow, but it looks like diesel in oil.on the day my car broke DPf came on on dashboard, orange color. Now I believe that is more likely a DPf that caused it. Am I wrong? Please any advice will do, I am going back to garage tmrw, I have screenshot loads of articles, I just need more. I feel like monkeys could do a better job in that garage.

Answer 1

Diesel getting into the oil is a fault - those « monkeys » are probably correct...

The usual cause is that one or more of the injectors has failed or become faulty and has been leaking excess diesel into the cylinders, washing down the bores and collecting in the sump.

This may need an engine rebuild (expensive) or it may just recover with repair or replacement of the injectors. A set of injectors may not be cheap either...

What happened to your car is not the fault of the garage or those « monkeys » so be nice. This happens sufficiently often and you should have found posts about it happening to several makes of car, it can be called "dieseling"...

Answer 2

Funnily enough I've had something similar to what Solar Mike suggests... happened with a much older, petrol engined VW Polo. ECU got fritzed by a faulty earth cable, and in the midst of trying to get it going again, before the root cause was spotted, it ended up dumping a good bit of the fuel tank into the inlet manifold, from where it leaked through (petrol - and diesel too - being quite a bit thinner than lubricating oil) the valves and then the piston rings into the oil sump. So then I had to change the oil and top up the petrol tank as well as replacing the earth strap and ECU...

It may not be the exact same cause here, but the otherwise inexplicable overflow, the appearance of what looks like fuel in the oil, the smoke, the sudden revving... sure sounds like what he suggests (an injector that failed by locking open, at least for a short period... they can have quite high flow rates when not operating in their usual intermittent fashion) would be the case.

DPF has almost no way of causing what you describe. The diesel particulate filter is usually a box living somewhere between your catalyser and silencer, i.e. halfway along your exhaust pipe, underneath the passenger cabin, a long way downstream from the engine, designed to catch soot particles in the exhaust. It has absolutely nothing to do with the fuel system or the oil. Perhaps you or other people advising you have become used to calling the general Check Engine / ECU or Sensor Fault light as the "clogged DPF light" as that's the main thing that it tends to come on for, or perhaps it's also lit up because the filter has become clogged (little wonder if the engine was suddenly overfuelling and producing a shedload of rather damp soot), but correlation in this case is certainly not necessarily causation.

I'd suggest getting a better grounding in the theory of your problem before mouthing off at the professionals who didn't cause your problem, might not have been fully briefed on the facts of the matter, and can only call it as they see it, which sounds like, at least from a very basic level, they got mostly right. (I almost wrote "but without getting the correct cause", but it doesn't sound like they even said a cause... they just said the oil level is too high, by four litres, which is quite a lot considering a typical car has about four litres of oil in it under normal circumstances ... unless you drain it out, separate it and examine it, you can't tell straight away that it's oil mixed with diesel fuel, and certainly not if you're just looking at a dipstick covered in some kind of substance coloured mostly by suspended soot particles. And that over-fill alone is enough to cause a lot of trouble, before even figuring out why it happened and how to to prevent a recurrence)