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  • Petrol in a diesel car
  • Premier Icon thegreatape
    Free Member

    After the relief of getting our son to his Covid test 100 miles away, my wife has just phoned to say she’s put petrol in our diesel car. Again. But this time, instead of filling it with petrol then driving it until it broke down, she realised after 1.9 litres of petrol had gone in. I told her to brim it with diesel and it’ll probably be ok – 55L tank capacity so about 97% diesel 3% petrol in there. And then fill it again at the next available garage.

    Am I right?

    Premier Icon grum
    Free Member

    My inexpert opinion says that way round and in those quantities yes.

    Premier Icon Joe
    Free Member

    Yeh should be fine. Enjoy your evening.

    Premier Icon thegreatape
    Free Member

    Thanks, I’ll try 🙂

    Premier Icon jam-bo
    Full Member

    It’ll be your fault…

    Premier Icon thegreatape
    Free Member

    Of course

    Premier Icon breadcrumb
    Full Member

    I’m sure my mate did the same, just kept topping up with diesel when down to ¾ of a tank for a while.

    Premier Icon andy4d
    Full Member

    Dunno how true it is but last time I did this a taxi driver in the garage said he occasionally does this on purpose to clear the injectors in his diesel, makes it run leaner or something. I had brimmed the bloody tank though so not an option for me.

    Premier Icon thegreatape
    Free Member

    I don’t know what mileage ours was at when she filled it with petrol and drove it, but we just got it drained and the filter changed and it’s not missed a beat since. So far 🤞🏼

    Premier Icon grum
    Free Member

    People used to commonly add a bit of petrol to diesel tanks before direct injection diesel engines, in order to stop issues with diesel in winter.

    I thought it wasn’t a good idea these days but in those quantities it should be reet IMVHO

    Premier Icon Cougar
    Full Member

    Again

    You know you can get cars which make this impossible? The filler is gated so a too-small nozzle won’t open it. First time I came across this was on a Focus at a Ford event where they were boasting about it, like 15 years ago. Might be something to consider next time you change vehicles (and to be brutally honest, if I were you I’d be looking to do that imminently).

    My inexpert opinion says that way round and in those quantities yes.

    Quantities yes, but “that way round” is the bad way round AFAIK.

    a taxi driver in the garage said he occasionally does this on purpose

    Can’t possibly imagine any ulterior motives here.

    Premier Icon alpin
    Full Member

    Done this years ago with my old 1.9 ibiza… Realised before starting.

    Tank was drained and brimmed with diesel. Cost me 20£ and never had a problem.

    Premier Icon beamers
    Full Member

    I did this in my brand new, at the time, Mk 4 Golf TDI.

    Me and a mate took it on a road trip from Harrogate to Tignes to go snowboarding for a week.

    At a service station in mid France in the wee small hours I got confused with the pumps and put half a tank of petrol into a quarter tank of diesel before I realised my mistake.

    So, we brimmed it with diesel and then cracked on, stopping at every service station that we came to and kept on topping it up with diesel.

    Car was fine and didn’t miss a beat for years afterwards.

    Premier Icon ji
    Free Member
    Premier Icon thegreatape
    Free Member

    Nice one – that’s her Christmas present sorted 👍🏼

    Premier Icon kenneththecurtain
    Free Member

    Fine in older diesels (I run a good few litres of petrol per tank of diesel in the landy in winter).

    Generally considered a bad idea in newer diesels as the modern pumps run at much higher pressures and are more dependant on lubrication from the diesel.

    Might not blow up after one or two occasions with small amounts of petrol, definitely won’t do it any good though.

    Premier Icon grum
    Free Member

    My mum had one of those mis-fuelling prevention devices on but forgot and thought the tank opening was broken or something so took it off and put the wrong fuel in anyway 🤯

    Premier Icon russianbob
    Free Member

    Mis-fuelling is often covered on your insurance policy.

    Premier Icon maurice
    Full Member

    I did this once while working for Avis, put a fivers worth of petrol in before I realised. Brimmed it with diesel and never heard of any problems with it. 2 litres should be fine.

    Premier Icon Drac
    Full Member

    My wife did this with one of ours, a modern diesel, only a small amount too. I got her to brim it full and kept it topped up for a few weeks. It give a little cough now and then for a week but was fine after that for at least 3 years.

    Premier Icon grum
    Free Member

    Since when is brim a verb btw? 🤯

    Premier Icon thegreatape
    Free Member

    Since always – thegreatape was brimming with enthusiasm that he might have yet another wife related car problem to keep him busy. But I don’t know if my use of it further up was correct or not 😀

    Premier Icon yetidave
    Free Member

    I did this after borrowing my managers car for a weekend. Didnt tell him I was driving to a wedding with a 1000mile return journey over the weekend. About 5litres petrol in a full tank of diesel. Engine management light came on for a while, then went off and was fine. I left the company shortly after that…

    Premier Icon thegreatape
    Free Member

    Well she made it the hundred miles home without a problem, which is an improvement on the quarter mile she managed last time

    Premier Icon CountZero
    Full Member

    The nozzle on a diesel pump is larger than the filler on a petrol car, so it could be easy to put petrol into a diesel car, the nozzle is smaller than the filler.
    I did manage to put £18 worth of diesel into a petrol car once, though!
    I had to fill up an Astra GTC, first time I’d ever driven one, and there was only one pump available, which required that I stretch the hose right across the car, and the mouth of the nozzle would only just touch the filler entrance, so I carried on and filled it up.
    Now, you might ask, why did I not check to see if the car was diesel or petrol first; I did, first I looked at the tacho, which showed a redline at about 5-6k, diesels are about 4.5k, so not sure, the clincher was the little black label stuck inside the filler flap that said diesel…
    The breakdown bloke who came to pick up the car from where it had stopped about a mile away had never seen anything like it, and it saved me from a £250 bill from my employer!
    And here’s the proof…

    Premier Icon bsims
    Free Member

    I thought the problem was the ethanol in modern petrol reacting with the material used for seals in more modern Diesel engines. Pre 00s a Diesel engine would just run roughly, now the problem is long term damage. This is also made worse by the very high pressure injectors on new diesels which also won’t then be lubricated.

    However 2 litres in 50 or so may not cause an issue. Even if it does I would think premature wear of components ra5her than catastrophic failure.

    Keep topping up just to be sure.

    Premier Icon captainclunkz
    Full Member

    Time for a divorce, I think.

    Premier Icon Drac
    Full Member

    Since when is brim a verb btw

    Always has.

    Premier Icon slackboy
    Full Member

    My missus managed to fill an mx5 with diesel.

    She said later she’d had to be quite persistent as the nozzle wouldn’t fit properly, 😂

    For balance I’ve put petrol in a diesel. Twice.

    Both times been ok. Luckily the garage that sorts it is next door to petrol station.

    Premier Icon Tom-B
    Free Member

    I’ve filled my diesel with petrol twice and then driven 20 odd miles each time before breaking down… engine hasn’t been quite the same since the second time. It is on 161k now though.

    OP sounds like a very stressful time for you all, hopefully everything is okay 👍

    Premier Icon thegreatape
    Free Member

    All good thanks Tom, test was negative.

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