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Will you investigate the reasons for my friend's Jaguar XF's engine developing a dangerous fault?

I am an ex-consumer adviser and am appalled by the way a friend has been treated by Jaguar Motors, and a Jaguar main dealer. Although there has been a short piece in the Evening Standard about his case (http://www.standard.co.uk/news/driver-sues-after-jaguar-sped-up-on-its-own-6397550.html), there is more to this story than meets the eye. Neither Jaguar nor the dealer appear to have any idea what really caused the problem with my friend's XF which could have killed him, twice, and since the engine was replaced after the first episode, that cannot be the remedy, so there would be little point in this being done again.

As another Jaguar owner has contacted the Evening Standard to say that he has experienced the same problem, involving the same model car and the same dealer, I thought you might be interested in investigating further and bringing this to wider public attention to see whether this is the tip of an iceberg?

Asked on 21 May 2011 by GM, via email

Answered by Honest John
The explanation for this is that the car has not been regularly driven far enough to regenerate its diesel particulate filters. As a result, the extra diesel fuel fed into the engine to regenerate the filters has dribbled down the engine bores and both contaminated and raised the level of the lube oil in the sump. Because a diesel engine is a compression ignition engine, once that oil level rises far enough for the engine to actually run on it, the engine speed cannot be controlled and the only way to stop it is either to stall it or to shut off its air supply. The former is impossible with an automatic. The latter would be extremely dangerous.
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