Misfueling

[ddave05]

Alright guys. Looking for some advice.

I leant my dad my passat (130 Tdi) over the weekend because he required the use of a larger boot than on his car. He chose to fuel it up because the tank was near empty, but the first 5-8 litres of fuel he put in was petrol. After he realised (without moving the car) he brimmed the tank with diesel.

He spoke to the attendant who told him it happens all the time, and that it should be ok as he brimmed the tank with the correct fuel. It's been running ok without any problems or splutters, but I swear its knocking a tiny bit. I just want to confirm that it won't affect the engine in the long term. When the tank gets to about half way, i will re-brim again with diesel to reduce the concentration of petrol in there. I hope this is a blessing in disguise (a free full tank of fuel :D) rather than a costly mistake....

[Cough]

Hello,

I hate to bear bad news, but having spent 8-yrs working in diesel fuel systems, my advice is Do NOT run the car until you've drained & flushed the entire system.
This measure costs c£120, but new injector pumps don't come cheap!

Diesel oil lubricates & cools the engine HP injector pump.
Typically, c60% of the fuel delivered to the engine HP pump is returned to the tank, while the engine takes c30%.

Petrol washes out the oil allowing the pump to overheat & seize. This can happen before you've left the forecourt or, more usually, within 1-week, dependant on the petrol / diesel fuel mixture in the tank.

If your car has other users, £15 buys you an aftermarket device that fits in the filler neck preventing misfuelling in future.

Cough

[ddave05]

Point taken. I'll probably give the AA a call and ask them to drain it for me. Cheers for the info

[stevegrass777]

I would take the risk myself.
There isn't a normal fuel pump just a tandem pump that is quite basic although they do fail sometimes.
And unit injectors.
My dad did exactly the same with no trouble.

This is the Tandem.

http://cgi.ebay.co.uk/Audi-VW-Tandem-Pump-for-1-9-TDi-engines_W0QQitemZ270366281386QQcmdZViewItemQQptZUK _CarsParts_Vehicles_CarParts_SM?hash=item270366281 386&_trksid=p3286.c0.m14&_trkparms=72%3A1683|66%3A2|65%3A12|39%3A1|240%3A13 18

Im not a booky so i can't give you the odds.
DYOR

[martin1810]

I would say that you have about 10 percent petrol which is about what some people add in very cold climates. I doubt this much will do any harm, especially if you keep topping up with diesel as the tank empties.

[moggies]

I would like to underline what Cough has said. It may have been acceptable with the older type of diesel systems that some petrol would have been ok, but these new high pressure crd type of diesels, its not.
It will all end in tears and an expensive bill. Beware!

[martin1810]

True but it's not a common rail diesel and doesn't have a high pressure fuel pump. I guess it's a pd which means the high pressure pump injectors might be affected.

[stevegrass777]

It's not new either this system was around a long time ago (cummings)

[zollaf]

i once worked for vw assistance. the official line from vw regarding this situation was that if upto 25% petrol was in the tank, to send the customer on their way, after topping up with diesel, and to top up as often as practical. this was on cars under warranty, and did not void the warranty.this does not apply to common rail engines, just pd and earlier.

[snapdragon]

I wouldn't worry as long as it was just <10 litres. The cetane will have been lowered by the petrol, so you may find the engine is noisier, lower power and harder to start. Avoid labouring the engine or very high rpms for an extra safety margin. You could add some Milllers Power Sport 4 if you wanted to be belts and braces. In fact, it will probably have done it good and acted as a fuel system cleaner!

[moggies]

My mistake, a tdi, with fingers crossed, will survive. So good luck and refill with diesel as soon as possible.

[dib]

I did exactly the same over two years ago (30000 miles) on my 100bhp pd Passat and have experienced no problems whatsoever. I put 7litres of unleaded in before I realised my mistake. I immediately brimmed it with diesel ran it gently to the 1/2 full mark and refilled it once again. If anything it seemed to run a little smoother for a while - less of that roughness that pds have especially at cold tickover.

[cazyp]

My moto is, 'drive it til it breaks...:firedevil'
A taxi driver I know put £20 worth of unleaded in a quarter full tank, 115bhp TDI. Drove 30 miles ( of lumpy running and smoke) before realising his mistake. Filled up with diesel. Drove it, filled up etc etc. That was @ 80'000 miles. He has now done 310'000. Same engine/pump etc. (Although I wouldn't recommend it:biglaugh:)

[jghccfc]

Put £20 of petrol in my Audi A3 TDI which had to be drained and repaired which cost me money and the inconvenience of being without a car for most the day. Found a device on the internet called Solodiesel www.solodiesel.co.uk which fits most vehicles. Arrived within 48 hrs and was so easy to fit. Will never have to worry again about misfueling my car again.

[passat 130 tdi]

saint johns wort - ebay £5.95 per 100 - excellent for memory loss/early dimentia and concentration levels. :biglaugh:

[snapdragon]

saint johns wort - ebay £5.95 per 100 - excellent for memory loss/early dimentia and concentration levels. :biglaugh:

Haha, :biglaugh: I'll remember that one!