What happens when I’ve put petrol into a modern prestige diesel vehicle?

19 July 2013 | glennwills

The weekend just passed we received a call from a rather desperate sounding customer. He had lent his 12 plate E200CDI Mercedes to a friend who had put 10 litres of petrol into the car, realised his mistake, then put 20 litres of diesel into the tank and attempted to restart. The vehicle refused. The owner was informed and his main concern was based on sound information – he’d heard that the latest high-pressure diesel systems, particularly those found in the higher end of the car market, are considerably more sensitive to mis-fuelling. These engine management systems work to considerably finer tolerances than in the past, running on higher quality diesel with the result of substantial improvements in efficiency and performance. However, if contaminated fuel is picked up by one of the sensors in many instances it will not allow the car to start/ run.

Our technician was informed of the details before setting off and was confident that he would be able to successfully get the customer back on the road. Upon arrival, he carried out a full drain, flushed the system with the correct diesel fuel after which he was able to successfully start the car. He advised the customer to fill the vehicle up with the correct fuel at the nearest opportunity and left to his next call out.