Filled Petrol into a 3.0 TDi Diesel Tank

[jaustin]

I have a Audi Q7 3.0 TDi and I have put petrol inside the diesel tank. A very silly and easy error to make. About 30 litres in total.

The key was turned to ignition but I stopped it after the engine turned twice, the car did not start at all (phew.) and I am hoping it is as simple as a tank drain and perhaps blowing out the fuel lines.

Does anybody know if this can be done? Do the fuel tanks have drain holes, I know there are two tanks. Is it an easy fix and are there are suitable instruction to carry this out anywhere that someone could provide the URL.

Your help would be appreciated.

Thank you.

[rayaans]

Just go to a dealer and they will probably give you a price of 800. Dont try doing it yourself because you will end up getting confused. Gosh, you've got a 39k car and you cant pay 800??

[jaustin]

Payment is not the issue, my dealer is.

In actual fact I am on the Customer Assistance Program with Audi because I along with many others have been having lots of issues with the dealer. There is only 1 Audi dealer where I live in Australia

Anyway, I was hoping to understand if its an easy task and would most other good mechanics be able to fix it.

The payment of 800 ($1700), however, does seem excessive for a tank drain and blowing pipes. I have read somewhere that newer models of cars start pumping fuel as soon as you unlock the doors so it is primed for starting. I suspect there is lots more involved

I also like to understand how things work, what the issues are and how a problem can be fixed.

[jaustin]

Well I didnt take it to the dealer. I had a local mechanic sort it out.

He originally thought he would have to take the prop-shaft off and drop the tank, however, he managed by emptying the tank through a hose pipe then removing the back seat where there are two inspection slots over the tank. He simply used a sponge to mop out all the petrol. He also blew out the fuel lines as well

The fuel filter was doused in diesel prior to putting it back.

There were issues starting up the car, the mechanic thinks there was an air lock in the system, he kept turning over the car, the battery went flat but after being re-charged the car started.

The whole cost was $850 over two days. An expensive mistake really but obviously happy it has all been sorted.

[Badger61]

It could prove even more expensive yet! The very expensive piezo injectors don't like, 1, being starved of fuel and 2, contamination with petrol. If the fuel system wasn't bled correctly they will be damaged and show up as misfires and poor fuel consumption in the future, I wish you luck but in my experience in a dealership after owners have taken the cheap route it has cost them dear later on, so it's a false economy. There is a reason the main dealer is expensive, it's a lot of work!!

I would also be concerned about turning over the engine till the battery was flat on this model, not good.

[Quacker]

Don't worry about it. Given that you didn't run the engine and that you drained the tank you will have no issues. I wouldn't even have bothered changing the filter or touching the fuel lines in that situation as it was a waste of time and money.
If in doubt throw a bit of Stanadyne or John Deere fuel additive in the tank with the diesel or even a pint [half a quart or litre] of two stroke oil.