Petrol in a Diesel Car in Underwood: How Worried Should You Be?
Probably less than you are now — provided no one has started the car. "Have I ruined it?" is the first question anyone around Underwood asks, and the truthful answer is normally no, since petrol resting in a diesel tank harms nothing until it's dragged through the system — by ignition priming, by the starter, or by being driven. Keep it that way: leave your motor off and phone Petrol in Diesel. Keep reading for three things: the effect petrol has inside a diesel engine, the signs of how far it has got, and the way to make sure you don't repeat it.
Inside the engine: what petrol in a diesel does
Two jobs fall to diesel on its route through a motor. Oiling comes before burning; it does both. The high-pressure pump and your injectors are designed to very fine gaps, and your diesel passing through them is what keeps those surfaces from grinding against each other.
Of those two jobs, petrol handles the first poorly and the second not at all. A pump working on a petrol mixture is wearing itself out, because petrol is thinner than diesel and takes away the lubrication your fuel system relies on. Petrol is also made to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that's where any rattling comes.
Seen together, they show the shape the trouble has. Contact doesn't do the harm — circulation does. All a tank with petrol in it amounts to is a fuel issue. Once the pump has been working on that petrol, a mechanical fault has started: whatever is shed by a pump that's wearing down travels onward to the injectors with your fuel.
How bad is petrol in a diesel? Four situations our engineers see in Underwood
The best case there can be: filled up, not once started. The petrol is inside the tank and just that tank, and the job is a drain and a flush where the car stands. This is the one situation that can only really occur at a forecourt, because anywhere else the vehicle has been driven to get there.
Ignition on, or started for a second. Petrol has come out of the tank and got to the filter and the lines, because your system has been bled. Normally little more than clearing, purging and seeing to your filter, and so still straightforward.
Some miles driven, and the pump has spent each of them labouring on diluted fuel. The work is your tank, the fuel lines, your filter and fresh fuel through the whole system, and how hard your car was driven matters as much as how far. Driving the kids to Underwood Church of England Primary School is one kind of trip. Any mileage on the M1, under 3 miles from Underwood, means the engine has worked hard throughout, and a run to Nottingham, under 10 miles away, makes a very different job too.
Driven till it protested. Clattering, an uneven idle, smoke, a throttle that has gone soft. The engine is telling you your fuel is no longer behaving like diesel. Pull up wherever you are — the verge on Smeath Road, a lay-by, a side street — then leave the vehicle where it is. The drain and flush still go first, and they take care of it: if a vehicle is stopped soon, lasting damage is very rare.
Petrol in a diesel stories Underwood motorists hear
False: topping up to full with diesel makes it fine. It does not. A fuller tank of the same mixture is all you get, since topping up takes out nothing. The idea behind the guidance — that diesel fuel systems accept petrol by percentage — is wrong.
"Newer diesels can handle a little petrol" — a myth, and closer to the opposite. At higher pressure, through smaller parts: that is how a modern diesel handles its fuel, and so the lubrication matters for more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that catches drivers. Diesel in a petrol motor normally means a motor that won't run: the driver stops, and so does the damage. A diesel fed petrol normally starts, ticks over and drives away as though nothing has happened, while the pump wears. Running is not the same as fine.
Not so: a two-stroke additive lets you to drive home. It is an old workaround, supposed for another issue. What petrol has weakened stays thinned, and that petrol stays inside the tank anyway.
Myth: "Drain the tank yourself and you are sorted." Once the engine has run, some of the petrol is no longer inside your tank: it is in your filter and your lines, and it goes right back through your pump at your next start. Emptying petrol into a can by the kerbside is also genuinely dangerous.
How does petrol in a diesel occur?
On purpose? Never. Through carelessness? Rarely, if ever. The petrol nozzle is the narrower of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol motor at all. The forecourt makes it simple, and the slip runs one way.
When routine and the vehicle stop matching, it takes place. Courtesy car, hire car, or a car that's brand new. One petrol and one diesel on the driveway of the same household. Your usual forecourt, its pumps now in a different order. A rushed fill en route to Langley Mill with a train to catch. A new-to-you diesel Renault Megane, its first fuelling, and a driver used to petrol: precisely when it takes place. Throw in rain, a phone call or a back seat full of children, and your hand does what it has always done.
How to prevent petrol in a diesel on your next fill-up in Underwood
- A green handle for unleaded and black for diesel is usual in the UK — yet not on every forecourt. Trust the label on the pump, not the colour.
- Inspect your filler flap. Plenty of motors state the fuel type inside the flap or on the cap. Look at it on the first fill in a motor you do not know.
- Mark the key. In a home with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It seems daft and it does the trick.
- While you are thinking about something else, this is an easy mistake to make — so put your phone away.
- Add-on devices are available for cars without one, and some diesels come with a filler that will not accept a petrol nozzle. Helpful — but a safety net only, never a reason to stop checking the label.
- Less petrol means a thinner blend, so stop as soon as you notice — though remembering that your next stage is unchanged. It's still not to crank it.
Underwood: already put petrol in a diesel?
Then the order of things is short. Don't turn your ignition on, and don't crank it. Still on the forecourt, at the nearest petrol station or anywhere else? Ask the staff to help you push it away from the pump. Then call 0333 366 0103 and tell us what went in, roughly how much, and if it has run.
If it was AdBlue rather than petrol, say so. That's a separate fault — corrosion and deposits and not lost protection — and it has its own page for Underwood.
One petrol in a diesel task in Underwood costs more than another. Why?
There's no honest single quote for this, since the four scenarios above are four different tasks. Which of them you are in is mostly what shifts your cost. The ratio matters next, meaning how much of your tank is petrol, and then the location of the car and whether reaching it is safe for a van.
That's why we ask three questions before pricing rather than after: what was put in, how much, and whether it's run. Their answers are what change a range into one firm number.
About Underwood itself
Underwood is a village in Nottinghamshire, situated inland at an elevation of around 138 metres, approximately 8.9 miles from Nottingham. Underwood has a population of around 1656 people and is characterised by predominantly detached housing. Underwood is located near other small places such as Friezeland and Bagthorpe, and is about 117.5 miles from London.
Underwood and Nottinghamshire: where our fuel drain cover runs
Friezeland, Plain Spot and Bagthorpe are among the spots around Underwood that the same teams work, answering petrol in diesel jobs across Underwood's NG postcode area. The car doesn't need to come to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Underwood: still at the pump?
In that case, you couldn't be in a better position. Phone, and leave it switched off.