1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Unleaded in Diesel car ??!!

Discussion in 'Motoring' started by super-saint, Jun 23, 2009.

  1. super-saint

    super-saint Member

    Joined:
    Oct 3, 2005
    Messages:
    362
    Trophy Points:
    21
    Ratings:
    +10
    Like a numpty I put £20 of unleaded in my old Peugeot 306 (R reg)...realised my mistake & then topped up with £30 of diesel

    Drove home (around 40 miles) ... car was jumpy & lacked power but was just about ok at a steady 60mph.

    Car has started OK this morning & have managed to get into work again this morning...again jumpy & blowing a bit of smoke.

    Now I guess that diesel is heavier than unleaded & should sink to bottom of fuel tank & thus be used first...therefore as along as i keep topping up (& hopefully eventually dilute the unleaded), do you reckon I can get away with it ???

    I did the same thing around 6 years ago :oops:...this time I filled the whole tank with unleaded.....drove around 2 miles & then phoned AA for assistance. Got towed to local garage, had fuel tank emptied, refuelled with diesel & then drove off - only charge was for the extra fuel. Now I assume I won't be so lucky should I phone AA today ?? -I guess i will be chaged for having the fuel sythoned off ?
  2. Solomon Grundy

    Solomon Grundy Active Member

    Joined:
    Nov 1, 2004
    Messages:
    12,065
    Trophy Points:
    136
    Ratings:
    +1,711
    I would phone the AA and see what they say.
  3. Jay J

    Jay J Member

    Joined:
    Apr 18, 2009
    Messages:
    867
    Trophy Points:
    43
    Ratings:
    +181
    I would also change the fuel filter in case any petrol got in there.

    I my mothers old 1991 Citroen AZ diesel owners manual it actually stated you could put 1 gallon of unleaded petrol into a full tank of diesel to stop the fuel waxing up in cold winters. I would not try these days because of the high pressures in the modern diesel fuel systems and fuel in winter now has special additives to prevent this waxing up.
  4. penno116

    penno116 Member

    Joined:
    Nov 14, 2006
    Messages:
    1,305
    Trophy Points:
    48
    Ratings:
    +78
    you should be ok,

    They did this on 5th gear years ago, the diesel car ran all day on petrol, but the other way round the petrol engine was completely stuffed.

    Granted it will probably cough and splutter for a while and i doubt you will get the best MPG out of it for a while.
  5. qwerty321

    qwerty321 Active Member

    Joined:
    Mar 20, 2009
    Messages:
    6,875
    Trophy Points:
    133
    Ratings:
    +948
    My dad did this once but many years ago. He said he accidently put some petrol in but topped it up with more diesel. Said the car went like a rocket afterwards!
  6. Rami Tupper

    Rami Tupper Active Member

    Joined:
    Sep 24, 2006
    Messages:
    295
    Trophy Points:
    31
    Ratings:
    +33
    it`s quite bad for the pump as it reduces the lubricity of the fuel but on an old low pressure injection system you might get away with it. youd be best advised to drain it, fill it with diesel and some millers diesel additive.
  7. Bilbob

    Bilbob Active Member

    Joined:
    Feb 21, 2005
    Messages:
    4,398
    Trophy Points:
    103
    Ratings:
    +295
    As said, on an old engine like that, pobably ok, but keep it topped up with diesel to dilute it as much as poss...then when it's running better, run it really low in the tank and fill up with diesel.
    As said, I would change the filter though once you are back to pure diesel.
  8. Neil Hawkes

    Neil Hawkes Member

    Joined:
    Sep 21, 2006
    Messages:
    412
    Trophy Points:
    28
    Ratings:
    +28
    It happened with our new car when about 6 months old. (Jag x-type).

    Once the diesel ran out the car stopped dead. Was towed away, drained, flushed and fitted with a new fuel filter, no problems thereafter.

    Don't remember the cost as it was 2 years ago, but it certainly wasn't much.

    The abrupt way the car stopped makes me think it was a safety feature in the engine management, to prevent any damage to the engine.

    Cheers,
    Neil.:thumbsup:
  9. johntheexpat

    johntheexpat Active Member

    Joined:
    Nov 15, 2006
    Messages:
    6,768
    Trophy Points:
    136
    Ratings:
    +1,282
    ?

    Its oil and water that don't mix. Oil and Oil should mix well. Run the tank as low as you dare, then fill up. If you have 50/50 mix (say, to make the maths easier) and use half, then fill up, you will still have 25% petrol.
    If you start with 50/50 and use 90% and then fill up, you will have 5% petrol.


    edit:
    Oh and add one of these fuel cleaners to clear away any soot etc that may have formed when driving on the wrong mix.
  10. Rami Tupper

    Rami Tupper Active Member

    Joined:
    Sep 24, 2006
    Messages:
    295
    Trophy Points:
    31
    Ratings:
    +33
    millers is the best value lubricity additive, it`s widely used by people who brew their own biodiesel, if your just going to run it through I would advise using some of that.
  11. Jay J

    Jay J Member

    Joined:
    Apr 18, 2009
    Messages:
    867
    Trophy Points:
    43
    Ratings:
    +181
    My dad has done it twice. The first time he accused the fuel station of selling watery diesel, but he told to look at the receipt and found unleaded. The second time was when claims to have been distracted by the wedding he was going to (not his) and out the wrong fuel in.
    :oops:

    There are such devises out there that will prevent you doing this. Ford have one on there new cars that will only accept a diesel nozzle and there are several after-market devises to prevent miss-fuelling. See:

    Fuel for thought | Products | Auto Express

    and

    Fuelsure | Products | Auto Express and their website FuelSure.com
  12. Hashim

    Hashim Member

    Joined:
    Sep 4, 2008
    Messages:
    382
    Trophy Points:
    28
    Ratings:
    +29
    the worst thing you did was top up the unleaded by filling it up with diesel afterwards.

    most car maintenance companies offer a debowse service which sucks the petrol from the fuel tank which would have done the trick for you.

    Although, most of us panic in these situations. You aren't the only one though.
  13. dejongj

    dejongj Well-Known Member

    Joined:
    Sep 11, 2003
    Messages:
    28,183
    Trophy Points:
    166
    Ratings:
    +4,353
    I wonder whether you would be so lucky with a modern common rail engine compared to your older one....The modern ones are much more sensitive I think...
  14. cunny678

    cunny678 Active Member

    Joined:
    Jul 2, 2007
    Messages:
    4,593
    Trophy Points:
    106
    Ratings:
    +387
    SWMBO filled up her two year old citroen with unleaded rather than diesel and then rang me when she had driven 4 or 5 miles and noticed it was a bit ruff and remembered what she had done. I told her to call the AA as she had the kids in and they sent a third party recovery truck out who towed it away and drained off the petrol.

    45 minuntes and £145 later and everything was fine:eek:
  15. Scholes18

    Scholes18 Active Member

    Joined:
    Oct 26, 2007
    Messages:
    3,895
    Trophy Points:
    106
    Ratings:
    +343
    Modern Tdi wouldnt handle it at all....
  16. Snatch

    Snatch Member

    Joined:
    Jan 14, 2006
    Messages:
    1,362
    Trophy Points:
    51
    Ratings:
    +96
    My advice would be to drain whatever is in the tank then fill up again using diesel.
    As others have said, i believe it should be ok if you continue to dilute the petrol, but probably not worth the risk of a potentially big bill..

    Wasn't there an after market device on Dragons den that stoppped this from happening?
  17. FZR400RRSP

    FZR400RRSP Well-Known Member

    Joined:
    Mar 5, 2007
    Messages:
    24,757
    Trophy Points:
    166
    Ratings:
    +4,137

Share This Page