The question is how much petrol can you put in a common rail diesel without wrecking it? The latest advice from people like the AA and RAC is that if you put even the smallest amount of petrol in your diesel tank you can’t even turn on the ignition (electric lift pump) without causing thousands of pounds worth of damage.
They say you must get the tank emptied and the system flushed. Of course they offer this service, at a price. The cost seems to be about £200 plus new fuel. Previous advice was if you put up to about 5 litres (10%) of petrol in your tank, just fill to capacity with diesel and carry on. What’s changed apart from making money draining tanks? Common rail diesel engines like the JTD and mJTD use very high pressures with precision pumps and injectors. These rely on the fuel for lubrication and modern petrol has low lubricity. This can cause galling and wear to pump components, possibly even seizure. The lubricity is provided by molecules that act on the surface of the metal, not a film like conventional oil. Sulphur was a significant provider of lubricity, but has all but been removed from modern fuels.
Back to the question, if I fill the tank of my 1.9l 16V150hp mJTD engined car with 50% petrol/diesel mix what will happen?
Robert G8RPI.
Back to the question, if I fill the tank of my 1.9l 16V150hp mJTD engined car with 50% petrol/diesel mix what will happen?
Robert G8RPI.
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