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put petrol in my diesel car and drove it anyway

richardg

Admonishtrator
I put 6ish litres of unleaded into a tank that probably only had 2 litres of diesel in it (7 miles left on the dash). I then added 48ish litres of diesel. My business partner did similar in his ML last month but put 20 litres in. So he took it to get drained (and it cost 900 euros, there are two tanks apparently, and they had to take the car half apart to get to them both). The mechanic said 5% of the total tank being unleaded could be enough to shag the engine. Its a Merc with very complex systems blah blah blah

So with around 12% of the total fuel being petrol in my BMW 120d, when is my engine going to shit itself and break down, please? I did 40 miles today and could not notice any difference at all.

After 40 miles I topped up with 4 litres of diesel to dilute the problem a bit.
 
Used to be a technique to get an old lorry through the smoke test, i'd risk it.

I did hear a Merc SL500 running on diesel, very rough and smoky, i wouldn't risk running that.

We used to have great fun letting people start diesels with oil bath air cleaners just after a good wash with petrol.

A really stupid thing to do.
 
Hmmm 4 pot diesel isn't it in your 120D, B58 is it?

Aren't they the ones renowned for shitting themselves when it comes to the timing chain etc?

Either eay; it could be that there's enough diesel in there to water the petrol down, so to speak... It could get very smoky too for a while...

How brave are you?
 
Hmmm 4 pot diesel isn't it in your 120D, B58 is it?

Aren't they the ones renowned for shitting themselves when it comes to the timing chain etc?

Either eay; it could be that there's enough diesel in there to water the petrol down, so to speak... It could get very smoky too for a while...

How brave are you?
Got a long journey to uk on saturday, but honestly, there were no noises, no stuttering, no clouds from the exhaust. I'll be topping up again tomorrow to dilute it further
 
Did the same with my old diesel jag. It was fine….just keep topping up with diesel as often as you can.

a bit of petrol might even clean the injectors for you. At the time my car was nearly new and the first diesel I had had, hence the mistake. I noticed and immediately swapped nozzles to finish the fill up. The car ran with me for another 9 years and 128k miles without any problem related to engine or fuel.
 
It shouldn't damage your engine but it will almost certainly have done damage to the fuel injection system. Is it a newish common rail diesel or an older injection pump model? The problem with petrol in diesel is it removes the lubricating qualities of the diesel fuel and then all the case hardened metal to metal high pressure generating components wear rapidly, putting case hardened swarf throughout the fuel system. Not good. If it is an older injection pump model, there's a good chance you might get away with topping up with diesel.
The usual first indication of this becoming a problem in the common rail models is bad starting. Fingers crossed.
 
I put 6ish litres of unleaded into a tank that probably only had 2 litres of diesel in it (7 miles left on the dash). I then added 48ish litres of diesel. My business partner did similar in his ML last month but put 20 litres in. So he took it to get drained (and it cost 900 euros, there are two tanks apparently, and they had to take the car half apart to get to them both). The mechanic said 5% of the total tank being unleaded could be enough to shag the engine. Its a Merc with very complex systems blah blah blah

So with around 12% of the total fuel being petrol in my BMW 120d, when is my engine going to shit itself and break down, please? I did 40 miles today and could not notice any difference at all.

After 40 miles I topped up with 4 litres of diesel to dilute the problem a bit.

As long as you did not drive on the majority gasoline 6G:2D mix (I understand that you immediately filled with 48 litres diesel) and keep topping up, you will probably be okay. Usual longer term issue for miss-fuelling and then driving a diesel car on a majority gasoline mix is increased probability of fuel pump failure, but this should not apply in your instance.
 
I would also top up with only Shell or BP Ultimate premium diesel fuel for the next few top ups as they contain extra additives which will help protect the pump. I wouldn't use anything else (and definitely no additives in a bottle) for this. Disclaimer - I work in the fuels industry.
 
I would also top up with only Shell or BP Ultimate premium diesel fuel for the next few top ups as they contain extra additives which will help protect the pump. I wouldn't use anything else (and definitely no additives in a bottle) for this. Disclaimer - I work in the fuels industry.

I was going to suggest bunging some Millers diesel ecomax in as well, sounds like you wouldn’t approve?
 
It shouldn't damage your engine but it will almost certainly have done damage to the fuel injection system. Is it a newish common rail diesel or an older injection pump model? The problem with petrol in diesel is it removes the lubricating qualities of the diesel fuel and then all the case hardened metal to metal high pressure generating components wear rapidly, putting case hardened swarf throughout the fuel system. Not good. If it is an older injection pump model, there's a good chance you might get away with topping up with diesel.
The usual first indication of this becoming a problem in the common rail models is bad starting. Fingers crossed.

This ^
 
My old Golf 1984 diesel had a chart for adding a proportion of petrol to lower the minimum starting temperature it went down to -25C which wasn’t a problem in Hampshire so I stuck with winter diesel.
 
My old Golf 1984 diesel had a chart for adding a proportion of petrol to lower the minimum starting temperature it went down to -25C which wasn’t a problem in Hampshire so I stuck with winter diesel.

Great car. I had a 1980 Golf diesel 1.5 as a student. Would run on anything!
 
If it were a diesel merc it would run on your piss, for the record I run two mercs and have been there, nowt to worry about
 
My old Golf 1984 diesel had a chart for adding a proportion of petrol to lower the minimum starting temperature it went down to -25C which wasn’t a problem in Hampshire so I stuck with winter diesel.
Ah, reminds me souvenirs...........
We accidentally put some pétrole in these as well for about half of the tank but immediately top up with diesel and never had any issues other than hesitating gas pedal.
We also used some heating oil when on a tight budget, smokey but okay until you get in a long slope going up........
Don’t say that to environmentalists !
Those little VW were pretty impossible to destroy but I don’t know about BMW or Mercedes.
 
I had a 1984 Golf 1.6d too. Bullet proof, 50mpg, never failed to start, never stalled. It was a bit rough but thoroughly enjoyable.
 
My old Golf 1984 diesel had a chart for adding a proportion of petrol to lower the minimum starting temperature it went down to -25C which wasn’t a problem in Hampshire so I stuck with winter diesel.

I bought mine in Hampshire in about '94. There weren't many on the roads back then. Was it red? LOL.
 
richardg - if you do go ahead with your trip, I would strongly advise having breakdown/recovery cover before setting off.

kendo - 33 years diagnosing, repairing, reconditioning diesel injection fuel systems.

(some...err...bold...advice being given here by some)
 


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