Hi,
Petrol in diesel fuel tanks can be dealt with in a couple of ways. If you have put a lot in and haven't started the engine, then you are best to get the tank drained and refill with diesel. If you have already started the car and driven it, you will be faced with a choice. You can top the tank right up with diesel to dilute the petrol, experts reckon as long as the petrol doesn't exceed 10% of the total fuel, you should be alright. Even if you have driven the car you may also opt for emptying the tank of its contents and refilling, change the filter too. Bear in mind that petrol is known to have a detrimental affect on seals etc within a diesel system, so even if your car seems ok now, keep your AA membership just in case.
Cheers now
Ken Chapman
May 2007