I would suggest that any oil 'sitting on top of the pistons' would have either been burnt or ejected out of the exhaust within the first few revolutions of the engine. And if the garage thought this might be a possibility, why didn't they just remove the glow plugs & turn the engine over a few times to eject it.

If the old faulty turbo had spewed oil into the intake then there would probably have been a lot of oil in the intake pipework & intercooler. The garage should have cleaned this all out during the work they did, but possibly took a shortcut & didn't do this.

So when the engine was started & had warmed the oil a bit it got blown into the engine. Being an un-regulated fuel supply the engine would just rev away to destruction or until it had used up the oil.

The 'technician' should have known that if a diesel runs away you can stick it in a high gear & stall the engine, or if an auto, block the air intake.

Once an engine runs away all sorts of damage can occure as heavilly built diesels don't like overrevving.

But proving any of this is going to be almost impossible now.

Perhaps a face to face between your friend & the garage manager, letting the manager know that his explanation doesn't hold water might extract a bit more of a financial contribution.

Agreed with the posters above. Rookie mistake, they didn't flush the oil out of the intercooler. Would idle OK, but a blip of the trottle would blow the oil out of the intercooler and hey-presto, instant runaway engine.

Also as said, turning off the ignition would do bog-all, you're trying to turn off a chemical reaction with a key. Stall it, or block the air intake, only way of stopping a runaway diesel.

Purely the garages fault, and their responsibility.

I had a similar dispute with Ford. In fact it still ongoing 2 years later.

My partner and I purchased 2 X Ford Focus 1.8 tdci's 2009 plates at the same time.

Mine within I months started to have engine problems which I was told was the injectors. These were changed after numerous trips to the garage. Just over a year later total engine failure - blown bottom end of the engine.

Ford quoted £11,000 and would reduce to £10, 000 for a replacement and auxiliaries, turbo and new injectors.

It had done 61,000 miles.

I took it to an independent garage as under sale of goods act need an independent report - this is another story - but he stated that there was an electrical failure - which makes sense - I never had any lights show as warnings. I now know that the service light should have shown which never did.

My partners car also failed this October 81,000 miles. Ford never even bothered to return his call. Maybe as I asked for someone other than the area manager to call. The area manager phoned and shouted abuse St me for raising a complaint about my experience of Ford - virtue group area manager for Staffordshire. He was very aggressive.