Mitsubishi ASX Diesel Problems

This is a very common problem for owners of modern turbo-diesel cars who only do short, stop-start runs in city or suburban traffic. When the engine and exhaust can’t get hot enough for a DPF burn-off, the computer dumps extra fuel into the engine to get everything hot. If some of this excess fuel gets into the engine’s sump, it can force the level of the sump to rise, leading to the warning light you’ve just seen.

In the worst-case scenario, this fuel in the sump will dilute the lubricating oil and that can lead to a damaged engine. But as you’ve found, even if that isn’t the case, there’s still a price to pay to manually force the DPF to burn off as well as change the oil for fresh, undiluted stuff.

The solution is to make sure you drive the car for at least half an hour at freeway speeds once or twice a month. That will get things hot enough for a complete DPF burn and will keep you out of the workshop. Mind you, making this sort of effort might cost you more than the fuel savings you gain from owning a diesel car. This is just one reason a modern turbo-diesel is not ideal for every consumer.

As long as the servicing has been done according to the Mitsubishi service recommendations there should be no impact on the EGR problem.

All diesel engines today have turbochargers, and believe me you wouldn’t want to drive a non-turbo diesel. Of those you mention I would go for a Mitsubishi ASX, or consider a Kia Sorento.

Carbon build-up is not an uncommon complaint with Mitsubishi engines; it's the EGR valve that gets gummed up by the re-circulated exhaust gases. There is no reason for the dealer to have your car for that amount of time, and there's no excuse for not telling you what's going on. If you can't get a reasonable explanation and outlook for getting back from the dealer/Mitsubishi consider going to the NSW consumer affairs department to get some action happening.

An air lock could have caused the problem. I doubt very much if your engine would have suffered any damage as the result of the short time it was low on coolant.