Good afternoon all, I have recently had a breakdown and recovery with the RAC (great service) after we had purchased a 2010 VW Tiguan 2.0 tdi and it stopped on the motorway without any warning at all! We were diagnosed at the roadside by the recovery unit who pointed to a few codes that point to fuel pump and pressure regulator but upon returning the car the the dealer he has tried to accuse us of putting wrong fuel in! Just out of curiosity how far would you expect a diesel engine to run on a tank of petrol before it actually died on you?!
Petrol in a diesel car.
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Community Manager06-02-25 16:59Hi @Gorgo78 , welcome to the RAC Community and thanks for making your first post. Whilst I'm not sure of an answer for your question I would suspect it depends on the car to some extent and I also think petrol into a diesel is the worst direction.
I found this article on our Drive site from last year that may have some useful information in it.
Article: What to do after putting the wrong fuel in your car
Do any of our users have any insights here or advice? -
06-02-25 17:09I'm happy to be corrected, but I actually think putting diesel into a petrol is worse - and also for the most part impossible as the diesel pump is bigger than the hole in most petrol filler caps?
In the Land Rover community people jokingly say that the occasional half gallon of petrol in the tank will do it good ... not advice I'd take but maybe based on experiences that it doesn't do lots of harm? -
07-02-25 12:13A lot depends on the manufacturer. Some seem to knowingly use plastics in the fuel system that break down in petrol, causing blockages in the pumps and filters. Some plastics seem to dissolve to the point that it clogs injectors. So depending on materials used, travelling a few yards, to a few miles, in an all metal and rubber setup with a mechanical lift pump.
