Here’s some advice if you need to do a DIY fuel drain to remove wrong fuel
If your car has an electric fuel tank pump, then there is a way to do a fuel drain yourself,
You need, containers (enough for all the fuel you have in the tank) 2 metre length of hose, and depending on type of car, some basic tools,
It is advisable if you also clean fuel (20 litres) to hand.
This works on most bmw, mercedes, citroen, peugeot, vw, audi, fords – if your diesel car makes a gentle buzzing noise for a few seconds when you put the key in the lights on position (the buzzing is the electric fuel pump priming the system) then this will most likely work.
This method is very hard on the cars battery and if it is not in good condition may flatten it, keep jump leads handy and another donor car, or be at the top of a hill
The skill level required to do this would take someone that is mechanically minded, and is aware of the safety precautions required when working with petrol and diesel.
1) Find the fuel line coming from the tank to the engine, you need to flow line to the engine, not the return line to the tank
2) disconnect the flow line and attach a hose to it, (you will need to get blue peter about it unless you have full garage facilities at your disposal)
3) put the other end of the line into a container
4) turn the key, not to starting position, just to pump priming position, this will activate the fueltank pump for 5 to 10 seconds which will send about a cupfull of fuel through the hoseline, then the pump will switch of again
5) keep repeating the same thing, turn the ignition off, then back to accessory position for 5 seconds, you might have to do this 200 times or more, it takes ages to drain a full tank.
6) once the tank is empty you will start getting foamy white fuel out, this is air that has entered the system from the empty tank
7) now pour in the clean fuel to the tank
8) repeat the key turning process again and again untill approximately 2 litres have gone thru, this purges the wrong fuel and fills the filter and lines with clean fuel
9) re-connect the fuel system and start the car
once the car starts you should fill it again to the top with clean fuel.
Petrol is highly flammable and this should be done in an area that is safe to do it,
Petrol in a diesel on new years eve,
Did a fuel drain yesterday on a 5 year old diesel Audi A3, it had been fill’d to the top with petrol,
The client had attempted to do a DIY drain but it’s not an easy car to do so I got called in, he had bought a new fuel filter which I fitted,
Here is a picture of the new filter (white) next to the old filter (black)
I usually don’t change filters, it is more effective to flush them out than to change them but the client wanted this done – and in all fairness the old filter was a bit manky so it was worth doing.
As you can see the filter is just fins made from a hi tech paper, if a diesel filter gets contaminated with petrol it can be flushed through with clean diesel which takes out all the petrol, this is a tried and tested method and is far simpler than replacing a filter
Filters should be be changed according to the service manual, some new diesels can go 15k miles between services, by which time the filters can be very mucky, a dirty filter can put strain on the fuel pump and if they get really bad it can cause a gradual loss of power
If you are using bio-diesel or vegetable oil I would recommend a fuel filter change every 2 or 3 thousand miles, its a very simple job and the filters are generally accesible to make changing easy.
Did a fuel drain today on the M23, an Audi allroad had been fill’d with 20 pounds of petrol (it was a diesel) and driven for 30 miles, the car had died and I got call’d, I did the standard drain & flush and went to re-start it, it wasent quite as easy as it should have been, and given the distance it had been driven I suspected major damage, I got some over the phone advice from an AUDI specialist – (turnd out that driven on wrong fuel audi allroad V6 TDI has a peculiarity) well I’m not too proud to admit that I don’t know everything there is to know about every car ever made, – and after some specialist advice on an unusual case – the car was up and running again with no further damage, and the customer was on his way, it’s worth having a few experts on hand at the end of the phone, and since its normally me dishing out the technical advice – it was a nice change (I made that all up, the truth is I was kicking myself – I make about 2 calls per year to other mechanics and I really could have done without that one because he will never let me forget it – )