Petrol in a Diesel Car

[jmh276]

My 04 reg Golf SDI started cutting out on me yesterday, then took a few attempts to start up again.I have had the same problem this morning so have taken it to my garage.I have driven it for about 20-25 miles since the problem first occurred They have asked if I put petrol in by mistake, to which I replied no. I am now rather paranoid that I have done.(I put �5 in yesterday evening on an almost empty tank).Colleagues have told me that the car wouldnt run at all if it had petrol in it.Especially with there being more petrol than diesel. Obviously the garage will find this out but I am asking for peace of mind as they cant get round to it for a couple of days.Cheers

[apex204]

If you put petrol in a diesel car you won't get very far at all, certainly not 25 miles. Doing this can cause massive damage to the engine because the way diesel and petrol engines work is totally different in terms of combustion and so on. If you have done this, though, it's not covered by your warranty as this is not a mechanical failure but human error. Expect a bill of around �3000.

[sense4all]

last year I put a small amount of unleaded in my diesel car,about four quids worth, I moved off the forecourt- to use mobile to dealer -and was told that as my tank was completely empty I could fill the rest to top about fifty quid without damaging engine.They told me to top up as soon as about five quids worth had gone for the next week or so.Car is fine. Had i gone over the magic percentage they said not to start the car,as it would instantly affect the engine, and we could kiss a large amount goodbye .... over a grand I think. Do you have the receipt, it may reassure you to read that. The kids have never let me live it down!

[gary baldy]

It may be anecdotal but some old timers claim that in t'olden days lorry drivers used to put a bit of petrol in their diesel tanks during the winter to stop it freezing up. A little bit does no harm but modern diesel engines are a bit more sophsticated so you could be in trouble (thats if you did put some in!)

[qapmoc]

The answer's above are virtually correct as far as possible damage etc.. is concerned.
I just wanted to correct a point really, a deisel type of engine will actually run on almost any type of fuel included petrol or parafin or vegetable oils etc... and you could drive for ever on that fuel, the BIG problem is that modern fuel injection systems and pumps are designed to run only on deisel fuel and will be damaged very quickly by any other fuel.

[BigB]

Hi jmh276

it is possible that the fuel you put in was diesel but may have been contaminated by water or something else.

[babyjaydee101]

Petrol in a diesel car usually wont do any harm, but you should not do it. Petrol burns in a slightly different manner to diesel, and there may be Catalyst, turbo and lambda sensor considerations. If the mixture is less than 50% you are probably safe enough. However if you run an expensive hi-tech modern diesel, it is better drain and refill the fuel system.

[babyjaydee101]

Petrol in a diesel car is not usually a problem, and if the mixture is less than 50% it is probably O.K. However a diesel engine is designed to run on diesel and there could be problems with catalyst converter, turbocharger and lambda sensor and your warranty may be compromised. So don't do it. If you drive the latest hi-tech expensive car its better to be safe than sorry, so drain and refill the tank. Otherwise, top up with diesel and you should be O.K. Diesel engines can run on central heating oil, cooking oil, bio fuel and petrol and nearly any mixture of the above, so don't let the low life in the motor trade bully you with lies and half truths.