Accidentally put a bit of unleaded in my diesel car, does it matter?

I'd have filled it all the way to be sure, but i'm sure it'll be fine.

I have done this a few times my car being diesel and my wife's being petrol, never had any probs but I have always filled up after I put a bit of the wrong fuel in. last time I put £5 of petrol in my diesel then had to put £65 worth of diesel in, much to my dissatisfaction.

Write off

It will not do any harm, in fact in very low temperatures, it can actually help, it helps to stop the diesel from freezing.

jonherb

Write off

. LOL you have helped the nerves

You'll be fine.

what car do you have?

EliTom

For 90p worth you should be fine,like someone else said adding petrol to diesel stops it from freezing which is what some people do in their lawn mowers but really only useful if you live in the artic you may notice abit of white smoke when you get to the bottom of the tank but I'd try and keep as much diesel in it for awhile now

knowing which car is important!

yes it's only about 2.5% mix but modern common rail diesel engines rely very much on the lubrication properties of diesel and this is removed by petrol.

so OP - which car? then I can give you some better / more informed information ..... rather than just you will eb OK / write off !

EliTom

omg sell the car.
the engine will now only last 900,000 miles rather than the 999,999 miles

if older car it will help clean you injectors so just fill it right up with diesel .

it will be fine.

in norway they add petrol to diesel. its called winter diesel.so you car will be ok

I done the same and was petrified to tell my husband as he is a mechanical engineer and was expecting a lecture but he said as it was such a small amount doesn't do any harm and said they often do it in colder climates anyway!

elitom

knowing which car is important!yes it's only about 2.5% mix but modern … knowing which car is important!yes it's only about 2.5% mix but modern common rail diesel engines rely very much on the lubrication properties of diesel and this is removed by petrol.so OP - which car? then I can give you some better / more informed information ..... rather than just you will eb OK / write off !EliTomRead lessRead more

2005 Astra 1.9 CDTI

Thanks all, sounds like nothing to worry about then

Dantooine

Thanks all, sounds like nothing to worry about then

hmm maybe ...

astra 1.9 cdti is a high pressure common rail diesel injection system - Bosch high pressure fuel pump - it is a version of Fiat's uniJet Turbo Diesel .... one of the first common rail diesel engines.

the problem here is that the high pressure fuel pump runs with extremely tight tolerances and lubrication is provided by the oils in the diesel fuel. Petrol trips these oils out of the diesel for want of a better terminology - try putting a bit of diesel on your hand and feel how oily it feels - now wipe your hand with a bit of petrol and note that the oily feeling has gone. Even running a high pressure fuel pump with a small amount of petrol can cause serious wear in the fuel pump and hence a failure at a later date. The same can happen if you run the car out of fuel - the pump will run dry for a short time - this is enough to cause permanent damage.

So it kind of pot luck really - you maybe lucky or you may have cause some premature / serious wear in the high pressure fuel pump.

Your call really - but yes there is some risk.

EliTom

Not that I've ever done it, but what about the other way around, a small amount of Diesel in a Petrol engined car?

if it still drives then no problem isn't it?

darkovo

Not that I've ever done it, but what about the other way around, a small … Not that I've ever done it, but what about the other way around, a small amount of Diesel in a Petrol engined car?Read lessRead more

in theory not quite as bad, the diesel will wax up injectors, but petrol will in theory wash the wax away

BUT unless it is a very old car it is neigh on impossible due to the smaller filler neck on a petrol car fuel tank. You would really have to put diesel into a unleaded fuel can then put it in the car tank ......

on very modern cars with direct injection gasoline engines the diesel will most likely clog the filters / injectors and the car will not run. if it does run then damage will occur to the catalyst and lamda / oxygen sensor - both are expensive to replace !

No real experience of this scenario because it is near impossible to re-create

EliTom

mutley1

if it still drives then no problem isn't it?

read post number 17

EliTom

I used work for a fuel company and we were always told tell the customer to keep the tank topped up for a while to dilute the petrol and its fine. 90p worth though, id say ur alright. diesel engines are hardy.
diesel in a petrol engine is a disaster though.

it will be fine but would suggest you pop into your local auto accessory shop or fuel station and by a bottle of diesel fuel addative and pop that in the tank.

jonherb

Write off

Not only a write off but huge fire hazard that will go up in a ball of flames while you're driving along the motorway. Wouldn't worry about it, if it had been the other way round then maybe but dont forget next time

My fiesta and newer model fords wont let you put the wrong fuel in, on the diesel will fit in mine and petrol in my other halfs car thankfully.

deiseaj058

I used work for a fuel company and we were always told tell the customer … I used work for a fuel company and we were always told tell the customer to keep the tank topped up for a while to dilute the petrol and its fine. 90p worth though, id say ur alright. diesel engines are hardy. diesel in a petrol engine is a disaster though.Read lessRead more

Never did my xr3 any harm , had the car a good few years after filling it with diesel with no problems

snoopy18

Never did my xr3 any harm , had the car a good few years after filling it … Never did my xr3 any harm , had the car a good few years after filling it with diesel with no problemsRead lessRead more

and the same logic holds true for modern engines?

EliTom

I put £20 worth of petrol in the wifes diesel focus the night before our wedding. It was midnight the night before our wedding we were driving back to her hotel after a family party and her car was low on deisel. I got out to fill her up with £20. my cars a petrol car so didnt think about it. We got about half a mile down the road and the car started juddering badly so we pulled over and she asked me what fuel id put in. So after a telling off we phoned the RAC for them to come to our rescue. They dont cover wrong fuel so it cost us £300 to get the car flushed out and the fuel system bled. 2 hours later the car was luckily running fine again. If we had of been with green flag it would of been free. We also lost the £20 of fuel and what was in the tank and also had to pay for the fuel he put in the car to get to the petrol station.

After that we still got married and while we were wating for the RAC we updated my speech for the following day

No problem with that small amount

elitom

and the same logic holds true for modern engines?EliTom

Stop scaremongering, the small amount involved will do no harm.

This ^^^

If it's fine now then it'll stay fine. I'd keep topping it up with diesel though to keep reducing the (already small) percentage of petrol.

With 90pence worth it should be fine. Had you topped up a few litres you would have needed to drain the fuel tank, but as other have said, just keep topping up with diesel and you should be fine

Cheers all, I'm not worrying now. May pop into my local garage to ask their opinion

Dantooine

Cheers all, I'm not worrying now. May pop into my local garage to ask … Cheers all, I'm not worrying now. May pop into my local garage to ask their opinionRead lessRead more

Wouldn't even do that as depending on garage will see you coming as its work

Just put in 6.2 litres of unleaded petrol into a diesal mini bus. When realised the error topped up with 51.94 of diesal. Should we worry???

elitom

in theory not quite as bad, the diesel will wax up injectors, but petrol … in theory not quite as bad, the diesel will wax up injectors, but petrol will in theory wash the wax awayBUT unless it is a very old car it is neigh on impossible due to the smaller filler neck on a petrol car fuel tank. You would really have to put diesel into a unleaded fuel can then put it in the car tank ......on very modern cars with direct injection gasoline engines the diesel will most likely clog the filters / injectors and the car will not run. if it does run then damage will occur to the catalyst and lamda / oxygen sensor - both are expensive to replace !No real experience of this scenario because it is near impossible to re-createEliTomRead lessRead more

Neigh on impossible means there's always a possibility....:{

birminghammail.co.uk/new…860. oO

Mazscl2016

Just put in 6.2 litres of unleaded petrol into a diesal mini bus. When … Just put in 6.2 litres of unleaded petrol into a diesal mini bus. When realised the error topped up with 51.94 of diesal. Should we worry???Read lessRead more

Drive it as normal and once the fuel gauge is half way just fill it up again to the top.

90p worth is about a thimbleful isn't it?

Hi guys I think I might of had the same problem only if I did then I believe I put about £10 worth of petrol into a deisel engine. I only ask because as I left work tonight I had a plume of white smoke come out of my exhaust. The car drove okay once I got going but im worried it might knacker the engine.

To Elitom -
What about petrol in the diesel of a Renault Megane diesel, 2011?