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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 22907
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I filled my diesel engine with unleaded a few weeks ago and

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I filled my diesel engine with unleaded a few weeks ago and drove 1 mile before realising, then got it drained and flushed and it has been fine since. Will there be any lasting damage?
Hello as you've only driven it a mile then you may be OK, especially if this mile was only at low speed and low load the key thing is how much diesel was in the tank before you filled up with petrol ? as you can cope with about 15% petrol in diesel so if its a 58ltr tank then you can get away with 9ltrs with the rest diesel I'd suggest adding a bottle of fuel treatment to give the pump and injectors some lubrication in the meantime
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Customer: replied 2 years ago.
there was about 1/4 tank diesel in at the time and i got is drained and added something similar to what you recommended to it before i filled up again. It is driving as normal since. I have had a problem with the clutch/brake fluid going low but i don't think this could be related could it?
Hello low clutch fluid won't be connected to this issue I'd check over the pipe connections and where the reservoir joins the master cylinder to check for any leaks
Customer: replied 2 years ago.
Cheers, ***** ***** what signs should i look out for if there is damage to the engine (apart from the engine management lights coming on)?
if you've damaged the diesel pump or injectors with the petrol then typically it'll start to become harder to start and also be down on power
I'd keep up the use of the additive for the next few tankfuls and I'd also recommend that the fuel filter is changed and that you use fuel from BP or shell as these both have additives to lubricate the pump
I've also found that while the high quality fuel is more expensive than the supermarket blend you also get more mpg so it does actually work out cheaper
Customer: replied 2 years ago.
Many thanks
glad to help