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What effect would 1.2 litres of petrol have on a diesel engine?

Discussion in 'A3/S3/Sportback (8P Chassis)' started by adamrawling, Nov 28, 2005.

  1. adamrawling
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    adamrawling Member

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    [Nov 28, 2005]
    Right then gents,

    Today, as I was filling my 2.0fsi up with petrol (don't worry about me!), some bloke enquired about what effect 1.2 litres of petrol would have on a diesel. He said he was filling his motor (a Vectra) up with juice but by the time he'd realised he'd got the wrong nozzle, he'd put 1.2 litres of petrol in it. He said the tank was pretty much empty and was contemplating just filling the rest of the tank up with diesel and carrying on regardless.

    Would the petrol (approx 2% of the tank capacity) be so diluted by the diesel that it wouldn't matter, or would it wreck the engine?

    I suggested that he phone the RAC or someone and ask. By the time I'd finished filling up and paid, he was sitting in his car with his phone to his ear.

    So I'm just curious, would he have got away with it if he had just driven the car off?
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  3. Dandle
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    Dandle Member

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    [Nov 28, 2005]
    Thats such a small amount he should be fine if he filled the rest of the tank with deisel. I would just take it a little easier for the next tank of fuel.
    #2
  4. h5djr
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    h5djr Well-Known Member VCDS Map User

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    [Nov 28, 2005]
    Probably. My brother drives a diesel VW Polo and a few months ago had a mental block and filled his tank with unleaded petrol by mistake.

    He phoned the AA and they said that, providing he had some diesel left in the tank when he filled up the petrol would sit on top of the diesel as it's much lighter. They suggested he drive home gently ( it was a Sunday) and in the morning get a garage to drain the tank and flush it out and refil it with the correct diesel and everything should be OK. It was and he had no further problems.

    Putting diesel into a petrol car is more of a problem as it sinks to the bottom of the tank straight away.

    As he had only put a small amont of petrol in he would not had to much of a problem, but it would have been a good idea to try and syphon the petrol off the top of the diesel at some stage.
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  5. adamrawling
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    adamrawling Member

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    [Nov 28, 2005]
    [ QUOTE ]
    Putting diesel into a petrol car is more of a problem as it sinks to the bottom of the tank straight away.


    [/ QUOTE ]

    Top knowledge - I didn't know that!

    Thanks.

    (I could make a joke about diesel being heavier than petrol .... but I won't!)

    /ubbthreads/images/graemlins/beerchug.gif
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  6. cdb2
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    cdb2 Member

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    [Nov 28, 2005]
    LOL

    "I could make a joke about diesel being heavier than petrol .... but I won't!" - that's Yak's job!
    #5
  7. bunny
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    bunny Member

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    [Nov 28, 2005]
    Wouldn't worry mate - in Germany we used to put some petrol in diesel cars to stop the tanks freezing in winter.
    #6
  8. marriedblonde
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    marriedblonde Moderator

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    [Nov 28, 2005]

    Yer mercedes used to recommend putting petrol in with the diesel in cold weather years ago.

    J.
    #7
  9. h5djr
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    h5djr Well-Known Member VCDS Map User

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    [Nov 28, 2005]
    Who said Diesel was thicker !

    But there again Petrol is a bit lighter on top!

    (With apologizes to Yak!)
    #8
  10. Horchsense
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    Horchsense Member

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    [Nov 28, 2005]
    Put couple o' squids of BP unleaded (with light blue nozzle colour) into A4 tdi - on empty tank. Filled rest of tank with £50 of diesel. Drove home no probs - phoned RAC - they said don't worry. Phoned Audi - they said "it will invalidate your warranty - have the car transported in immediately". Even a tiny amount of petrol will dilute the engine lubricants that are vital to high pressure Diesel systems.

    It was common practice in old fashioned Diesel engines to dilute the fuel with petrol in the winter - some lorry drivers used to light a fire beneath the fuel tanks to "thin" the fuel. But modern direct injection systems are not the same.

    Phoned RAC who obliged with low-loader. Service manager told me that BP had recently appeared on Watchdog - 'cos "lots of people had put light blue nozzle in Diesel tank" - (Light blue is Esso Diesel 2000 colour I think)...Phoned BP customer services - they refunded £150 (Audi dealer labour charge) for draining tank plus £50 worth of Diesel. Moral? RTFM maybe - or at least the pump...
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  11. marriedblonde
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    marriedblonde Moderator

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    [Nov 29, 2005]
    Do you really need to read the manual to know that you should put diesel in a diesel car and petrol in a petrol car...

    Do you have little notes on all the knives in your house "Do not stick into leg" /ubbthreads/images/graemlins/laugh.gif
    #10
  12. d3fy
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    d3fy Active Member

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    [Nov 29, 2005]
    I have not had a oil burning in 5 years but for some reason I always double check the nozzle before it goes in, always.
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  13. marriedblonde
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    marriedblonde Moderator

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    [Nov 29, 2005]

    I went to fill the wifes car up sunday night and had to check three times before I pulled the trigger!
    #12
  14. Horchsense
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    Horchsense Member

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    [Nov 29, 2005]
    [ QUOTE ]


    Do you have little notes on all the knives in your house "Do not stick into leg" /ubbthreads/images/graemlins/laugh.gif

    [/ QUOTE ]

    Man goes to the doctor with knife & fork marks on his forehead - doctor says "you're not eating properly" (apologies)...

    Colour coding can be confusing - Diesel usually black - but often yellow - Esso light blue, BP navy blue etc. We're all human - easily done if you're tired stressed etc...BP accepted their responsibility for creating confusion and paid up...
    #13
  15. alan braine
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    alan braine New Member

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    [Feb 4, 2014]
    iv just put a tenners worth of petrol in my a3 diesel and toped up with 58quids worth of diesel and drove home do you think things will be ok
    #14
  16. sliced
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    sliced Drive safe, stay alive.

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    [Feb 4, 2014]
    [​IMG]
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  17. mjr901
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    mjr901 Parts Manager - (Main Dealer)

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    [Feb 4, 2014]
    I used to work for a petrol station, happens all of the time,

    It won't even notice mate at those ratios.

    Just fill again at 3/4 and 1/2 to be sure it dilutes.
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  18. DriverN00B
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    DriverN00B Member

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    [Feb 4, 2014]
    From the sounds of the thread, the diesel will have sunk to the bottom and the petrol will be at top. So when your tank runs low, it could cause issues as a tenner is quite a bit if it hasn't just diluted and mixed. Personally I'd get it drained from a garage.
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  19. DriverN00B
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    DriverN00B Member

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    [Feb 4, 2014]
    That'll do the trick, refilling and making sure it does mix! Good little trick thanks.
    #18
  20. alan braine
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    alan braine New Member

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    [Feb 4, 2014]
    thanks for the advice fingers x and i will just keep toppin it up will keep yea posted
    #19
  21. Andy Crooks
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    Andy Crooks Well-Known Member

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    [Feb 4, 2014]
    A small amount of petrol can go into diesel but diesel can't go into a petrol
    #20
  22. Sayam
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    Sayam Active Member

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    [Feb 5, 2014]
    If it was my car I wouldn't worry at all with £10 petrol and tank full of diesel. I'd just drive it...
    #21
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  23. Boon
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    Boon Active Member VCDS Map User

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    [Feb 6, 2014]
    Diesels will run on pretty much anything liquid and burn-able. Petrol will dry out the seals in pumps but not at quantities said above

    Fill up with derv and all will be fine (a tiny bit of mineral 2 stroke oil will help with lubrication too :) )
    #22
  24. Alex_007
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    Alex_007 Member

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    [Feb 8, 2014]
    I put over half a tank of unleaded in my tdi and it didn't make any difference , still ran ok .
    #23

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