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MG MGA - Diesel in the tank!!

Drat - just put a full tank of diesel in my car which had less than a quarter tank of petrol in it. It ran for about a mile stuttered then produced a cloud of white smoke and stopped.
I'm home now after the AA picked me up but I haven't drained the tank or fuel lines yet. I'm wondering if there will be any more damage done by leaving it overnight? I'd welcome any thoughts.

I normally go by the colour of the fuel nozzle and I feel sure that the nozzle was green but it might have just been the ad on the nozzle handle that was green. Very annoying.
John Francis

My father did that once in his Wolseley 1300.

After towing it home, I just pumped as much as I could out of the tank and emptied the float chambers.

No lasting damage.
Dave O'Neill 2

You are talking to an expert here John, I have put petrol into my diesel car three times! ( Yes 3 times! and I still cant really tell you how I did it.)

Now putting petrol into a modern diesel car can cause a serious problem as it can destroy the fuel injection system. So you have to drain it out.

But diesel into a petrol MGA is just annoying, even if it has got to the carbs, the worst it can do is stop the engine like you have found.

If you just drain the tank, then put some fresh petrol into it.
Then drain the float chambers and switch on the fuel pump to flush the diesel from the system.

When you restart the engine the exhaust may be a bit smokey for a day or so until the last remnants of the diesel is burnt off.

But this only has the same effect of adding too much upper cylinder lubricant to your petrol and you should be back to normal in a day or so.



(The biggest problem is finding enough cans to drain 10 gallons of petrol /diesel mixture into and how to dispose of it)
Colyn Firth

Drain it will be fine! lol!

Oh well all fixed now. Pumped most of the tank out and luckily my neighbour had another two big containers to go with my jerry can to put it all into. I then drained the tank completely and took the tops off the float chambers and sucked out the fuel in the bowls with a little plastic dropper. I disconnected the fuel line from the carb cross feed pipe and poured less than a quarter of a gallon into the tank and pumped it through to a small container. I was surprised at how good the pump pick up is with a tiny amount of fuel.

I should have pumped it through with no petrol in the tank first to know when petrol was first coming though. I repeated this one more time. Lastly after connecting it all up I took the plugs out and cleaned them and turned the engine over with the fuel pump on. This got some clean petrol into the cylinders and helped clean the jets out. Finally put the plugs in and started it. It fired first time with no smoke and just a few black smutts.

Fuelled it and went for a run and it seems to perform perfectly OK. As you said Colyn now what to do with nearly 50li of diesel/petrol mix at 85/15 mix? I'm not putting it into my Merc even diluted further. Its illegal to keep more than 30li at home so I need to find a solution soon.

John Francis

Glad you have it fixed John.
You now have probably 20 years supply of barbecue lighter fluid! ☺

You will probably find a local garage who has a contact for disposal of the fuel.
Colyn Firth

I dont think you need to worry about getting every last drop out of the tank. I put a gallon in by mistake a couple of weeks ago before realising because of very similar labels between standard diesels and petrol Shell signage. My excuse anyhow! I just filled the rest of the tank with petrol and with 10% diesel it ran fine. Clearly you need to get the 100% diesel out of pipes and carbs but not tank.

Paul Dean

Hi there if you have another car just feed the mix petrol + diesel into it bit by bit when the tank is full or almost full, good lubricant

This thread was discussed between 30/07/2016 and 04/08/2016

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