Should You Worry? Petrol in a Diesel Car in Hampton
Far less than you likely are, if it hasn't been started. Everyone in Hampton starts with "have I wrecked it?", and the fair answer is usually no: petrol left inside your tank of a diesel remains harmless till priming, cranking or driving pulls it into the fuel system. Keep it that way: leave the engine off then ring Petrol in Diesel. What petrol actually does to a diesel, how to judge how far it has travelled, and how to stop it from happening again: that's the remainder of this page.
The motor and petrol in a diesel: what goes on
Diesel has two jobs on its way through an engine. It protects to begin with, and only then does it burn. What keeps the surfaces inside the high-pressure pump and the fuel injectors from wearing down against each other is your diesel passing through them — they are made to extremely fine gaps.
Poorly at the first, not at all at the second: that is petrol. A pump working on a petrol mix is wearing itself out, because petrol is runnier than diesel and strips out the protection your fuel system depends on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that's where any clattering starts.
The shape of the problem is plain when you put those together. It's circulation that causes the damage, not contact. Petrol in the tank is a fuel fault. A pump that has been running on that petrol is the start of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the fuel injectors further on.
Four scenarios we see in Hampton: how bad is petrol in a diesel?
Filled but not once started — as good as it gets. Just the tank has petrol in it, so the job is emptying the tank and purging the fuel system where the car sits. This situation can only really take place on a forecourt: anywhere else, the car got there by being driven.
Ignition on, or started for a second. Once primed, the fuel system has pulled petrol out of the tank up to your filter and the lines. Still generally easy: drain, flush, and the fuel filter seen to.
Those few miles on the road meant your pump working on fuel diluted by petrol the whole way. Mileage is only half of that; how hard it was driven counts just as much. Either way the work runs to the tank, your lines, the fuel filter and clean fuel through the entire circuit. The school run to Carlisle Infant School is one thing. A run as far as Westminster, under 15 miles away, is a very different job. So is any miles on the M3, under 3 miles from Hampton, where your engine has been labouring hard throughout.
Rattling, a ragged idle, smoke, a throttle gone soft: driven till it complained. The fuel isn't behaving like diesel any more, and the engine is saying so. Pull up on the spot — on the verge on Broad Lane, at the kerb, down a side road — and do not move it again. The fuel drain and flush-through still go first, and they take care of it: if a car is stopped soon, long-term damage is very uncommon.
What Hampton motorists get told about petrol in a diesel — and the myths in it
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Nothing is removed when you top up — the tank simply carries more of the same blend. Percentage is not how a diesel fuel system copes with petrol, however much that advice supposes.
Myth: a modern diesel copes with a bit of petrol. Rather, the opposite. Lubrication counts more on current diesels, not less, since their fuel passes through finer parts at higher pressure.
This is the one that catches people. Myth: "If it starts and drives, there is no damage done." Feed diesel to a petrol engine and it normally will not run, so the motorist stops — and the harm stops with them. Feed petrol to a diesel and it normally fires up, ticks over and pulls away like nothing happened — all the while its pump wears. Fine and running are not the same thing.
An outdated fix for a different fault lies behind this one. Myth: "Add some two-stroke oil and drive it home." None of what petrol diluted gets put back by it — and afterwards, that tank still holds the petrol.
"Drain it yourself and you are sorted" — a myth, because after it has been running some petrol lies in the fuel filter and lines, ready to go right back through the pump on the next start. On top of that, petrol emptied into a can by the road is truly hazardous.
Why petrol in a diesel takes place at all
It's rarely carelessness, and nobody does it on purpose. One way only, since of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, while the diesel one mostly will not fit a petrol vehicle. That is how the forecourt makes it simple.
When routine and the car stop matching, it happens. Hire cars, courtesy cars, and vehicles that are new to you. Two motors on one drive, one petrol, one diesel. Your usual forecourt, its pumps suddenly in a different order. A train to catch, and a rushed fill on the way to the nearest station. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that's when. Add rain, a phone call or a back seat full of children, and the hand repeats what it has always done.
Hampton drivers: how to avoid petrol in a diesel next time
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most generally do. Check the petrol pump's label; the colour is only a clue.
- Plenty of cars state the fuel type inside the filler flap or on the cap, so check it on your first fill in a vehicle you don't know.
- One of each in the household? Label your key to the diesel — a bright fob, a sticker — since intending to remember is not enough.
- It sounds daft and it does the trick: on your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump.
- Tuck your phone away. This is an easy mistake to make whilst you're thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to refuse a petrol nozzle, and add-on devices are available for cars without one. They are a backstop, not a reason to stop checking the petrol pump.
- Less petrol means a weaker blend, so stop as soon as you notice — though remembering that your next step is unchanged. It's still not to fire it up.
Hampton: already put petrol in a diesel?
The order of things is brief, then. Leave it unstarted, with your ignition off as well. Yet at the forecourt, at NPL Hydrogen Station or anywhere else? Ask the attendants to help you push the vehicle clear of the pump. Next, 0333 366 0103. We will ask what got in, roughly how much, and if it's been run.
Say so if it was AdBlue instead of petrol: it's a different issue, with its own page for Hampton, because AdBlue brings corrosion and deposits instead of lost lubrication.
Hampton petrol in a diesel tasks: why one costs more than another
The four situations above are four different tasks, so no single price for this would be fair. Which of them you are in is mostly what moves the cost. Next it is the share — how much petrol went in against how much your tank takes — and after that where the vehicle is and whether a van can get to it safely.
That is why our technicians ask three questions before quoting instead of after: what went in, how much, and if it has run. Their replies are what turn a range into one firm number.
About Hampton
Hampton is a locality in the London Borough of Richmond upon Thames, situated on the north bank of the River Thames at an elevation of around 18 metres. Hampton sits within a short distance of nearby places such as Hampton Hill, Fulwell, and Teddington, and is located approximately 11.7 miles from central London. Hampton has a population of around 2675 people and is characterised by predominantly detached housing.
Fuel drain cover in Hampton and across Greater London
Our teams answering petrol in diesel calls around Hampton, in the TW postcode area, also work the spots near it, Hampton Hill, Fulwell and Teddington included. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our engineers work, and your car doesn't need to move to us.
Hampton: still at the pump?
Nothing beats it: that's where you now are. Call, and keep it turned off.