Putting Petrol Into A Diesel Car #TBT - Fifth Gear

[Music] this is one of the most embarrassing mistakes you can make it's easy to do and hundreds of thousands of drivers do it every year ah the schoolboy error in question is called miss fueling putting the wrong sort of fuel into your car whether petrol into diesel or diesel into petrol more than one in seven of us have done it men are twice as likely to commit this humiliating error as women and I'm told some of the most frequent miss fuelers are police officers your garage is likely to prescribe a new fuel tank new fuel lines and useful pump new injectors in fact the whole school system and a cost of thousands of pounds factoring the environmental problem of disposing of contaminated fuel and you can see why miss fueling cost British motorists millions of pounds a year sometimes your insurance will cover the mistake but often in quote but is it really necessary to replace everything or would say a quick blast down the road with the right fuel be enough to sort everything out to find out I bought a couple of old cars one diesel and one petrol are we gonna see how they cope on the wrong fuel first I'm going to try putting diesel into a petrol car now in practice diesel nozzles are slightly wider than petrol ones and any petrol car with a catalyst should have a narrower fuel filler neck that prevents miss fueling but even though it's a really hard push to get it in over 20,000 people make this mistake every year now in a petrol engine the power is produced by the spark plug igniting a compressed mixture of petrol and air but diesel has a much higher flashpoint than petrol meaning it's much harder to ignite so there's a possibility the engine just won't go at all [Music] the tank in our escort was nearly empty of unleaded and I'll be putting in five liters of diesel the sort of amount you might put in on the forecourt before realising your mistake right let's try it starts okay into drive it's called automatics well we're going which is a good thing at first the diesel in a petrol car didn't seem to have any unusual effects but after a few minutes the car started to shudder [Music] we'll have to do something this is Potter not a very well car at all I've got about a couple of miles in it and some of the time it runs pretty well other times it gets into sort of bouts of hiccupping so I think it's probably time to siphon off this contaminated fuel put in some fresh unleaded and see if we can restore it to health which is easier said than done this car seemed to be fitted with an anti siphoning device so we abandoned the idea left the diesel in it and filled it up with its usual petrol surprisingly after a few minutes the car seemed pretty much back to normal but has its brief encounter with the wrong fuel damage the catalyst we did an emissions test to find out it passed so putting diesel into your petrol car doesn't seem to be a disaster at least once you've recovered from your initial loss of face but without putting petrol into a diesel putting petrol into a diesel is much more common it's much simpler to do the slim unleaded nozzle slips into the broader diesel filler easily oops now this car was nearly empty of diesel very soon is can have 5 litres of petrol in it is it gonna be instant disaster this time I wasn't worried about the screaming fan belt the Astra had been doing that since I bought it [Music] and amazingly to be running okay that could be leading me into a false sense of security you see petrol unlike diesel has no lubricating effect and it's particularly likely to damage the fuel pump a more modern diesel would be much more likely to be damaged by now because the pumps run at much higher pressures and to tighter tolerances but I've driven up and down for around 15 miles and the Astra seem to be running on petrol very happily hey if anything feels a bit quicker [Music] [Applause] [Music] after about half an hour playing around the only signs of anything wrong were sparks falling from a newly-developed hole in the exhaust apart from that the car had been running fine but then during our emissions test things took a turn for the worse not try to get was it wasn't he's owed money to just flat it's gonna stop ah that's amazing you could to stop it on the track but it's actually stopped doing his emissions test hmm let's try and start it again company Biko ah those are like that it's not going that's not going not give up on the Astra yep gonna try burning diesel ins if we're gonna store it to life maybe if I filled the tank with its original fuel I could flush out the petrol and have it up and running again the moment of truth [Music] strange noises [Music] it looks like a victory but then the engine died again eventually after a few attempts I had it working again the diesel was starting to run through normally the smoke gradually turned to the right diesel II color time for a test drive and it was fine the very next day I went shopping in it the day after that I took it for a children mile drive on the motorway certainly proves you don't always need to replace the fuel system at great expense though I would suggest you have the fuel tank drained professionally if your car's worth more than mine and I don't suppose a highly tuned modern diesel would be so robust but this exercise certainly restores your faith in old bangers oh I think it's quite high up there you think [Music]

Channel: Fifth Gear

Views: 14,724,267

Keywords: Fifth Gear, car, review, fast, crash, fifth, gear, Tiff Needell, Jason Plato, Vicki Butler-Henderson, Jonny Smith, car review, Putting Petrol Into A Diesel Car, Jon Bentley, Putting gas in a diesel car, gas

Id: GL9-i9tcESU

Length: 7min 35sec (455 seconds)

Published: Thu Dec 17 2015

Reddit Comments

[u/trevdak2]

My sister once accidentally put diesel in the lawnmower, and it wouldn't shut off. She had to keep going around with the mower for something like an hour before it stopped.

[u/sirgallium]

Funny you posted this, I just watched it on youtube earlier and enjoyed it. I had always wondered what would happen.

Although the result may be different with modern diesel and gas engines that are so reliant on computer control and also the modern diesels have quite an array of emissions equipment that could maybe be damaged.

Who knows, maybe the new cars are so smart they will detect the bad fuel and shut off.

[u/[deleted]]

Having just purchased a new Diesel Pickup, I fear this happening as i've not had a diesel in years and the wife has never had one.

[u/[deleted]]

Not sure how viable it is but a local taxi driver (Skoda Octavia Diesel) claims to stick 20% petrol and 80% diesel in his tank every time he fills up in winter to "help with the cold."

Although he could have just been chatting shit to fill the time.

[u/[deleted]]

I've always had the thought of "What if this is diesel?" when filling up my truck. Glad to see it's not completely disastrous. Still need to be careful though!

[u/mrcheeseweasel]

I have a 2005 Pontiac wave. Filled the tank from half full from a jerry can that had deisel, I got the mail and got home and it wouldn't start next time I needed the car, realizing then that I had put diesel in. Pumped the tank dry, filled with gas, opened a Schrader valve that was right after the pump, put a hose from it to a pail, then turned the car over for a bit. 20 seconds on, 30 off. After a bit I closed the valve and the car started, risked coal for a bit but eventually ran normally. Nothing wrong with it so far.

[u/outtyn1nja]

This is good, practical, science!

[u/IP00P]

Rented a newer diesel Opel Suv (2-3 years old) few months back and accidently put about 10 liters (70 liter tank) of gasoline. Workers at the station just told me to fill the rest with diesel and keep topping it off every few miles. Car ran perfectly fine. I felt so stupid doing it, and freaked out once I realized the problem.

[u/murkleton]

Worked at GreenFlag breakdown for quite a while. Blokes would often get their wives to ring up because they were too embarrassed - they would always spill the beans and tell me their husband did it. I'd ask them to put them on the phone 'so I could get some details.' Really I just wanted to hear the humiliation in there voice.