Should You Worry? Petrol in a Diesel Car in Roxeth
If it has not been started, worry far less than you likely are. Petrol sitting in a diesel tank does nothing to the engine till something pulls it through the fuel system — the ignition priming the pump, your starter, or driving on its own. So the honest answer to the first question everyone in Roxeth asks, "have I wrecked it?", is generally no. Keep it like that: leave the engine off and call Petrol in Diesel. The remainder of this page sets out what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you a second time.
Your engine and petrol in a diesel: what goes on
Diesel does two tasks on its way through a motor. It combusts, and before it combusts it protects. What stops the surfaces inside the high-pressure pump and the fuel injectors from wearing down against each other is the diesel passing through them — they're designed to very fine tolerances.
Petrol does the first job badly and the second not at all. It is thinner than diesel and removes the protection the system depends on, so a pump running on a petrol mix is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the rattling comes from.
Put those together and the shape of the problem is clear. Contact does not do the harm — movement does. All a tank with petrol in it amounts to is a fuel fault. Whatever a worn pump sheds goes on, borne by your fuel, into your injectors downstream, which is why a pump that has worked on the petrol is where a mechanical problem begins.
Roxeth, petrol in a diesel: four situations, from mild to significant
Fuelled up, not once started. The best case there is. Just your tank has petrol in it, and so the task is emptying your tank and flushing your system where your car sits. This scenario can only really happen on a forecourt: anywhere else, the vehicle got there by being driven.
Started for a second, or only your ignition on. Once primed, the system has pulled petrol from the tank as far as your filter and the fuel lines. That is generally still a simple task — a drain, a flush, and the fuel filter seen to.
Driven a couple of miles. Now your pump has spent those miles labouring on diluted fuel. Mileage is only half of it; how hard it was driven counts equally. Either way the work runs to your tank, the fuel lines, the filter and clean fuel through the whole circuit. The school run to Roxeth Primary School is one thing. Driving as far as Westminster, under 15 miles away, makes a very different task — as does any miles on the M1, under 5 miles from Roxeth, with the motor running hard all the way.
Driven on till it complained — clattering, smoke, a ragged idle, a soft throttle. What you are hearing is the motor signalling fuel that no longer runs like diesel. Leave it wherever it has stopped: a lay-by, a quiet street, the verge on The Crescent. Long-term damage is very uncommon if a car is pulled over early, and the fuel drain and flush-through that still go first take care of it.
Myths Roxeth motorists hear about petrol in a diesel
Myth: topping up to full with diesel makes it fine. It doesn't. A fuller tank of the same mix is all you get, since topping up removes nothing. Percentage is not how a diesel fuel system copes with petrol, however much that advice presumes.
"Current diesels can handle a little petrol" — a myth, and nearer the opposite. At higher pressure, through more precise parts: that is how a newer diesel handles its fuel, and so the protection counts for more, not less.
"It starts, it drives, so there is no harm" — the myth that catches most drivers than any other. Feed diesel to a petrol engine and it usually won't run, so the driver stops — and the harm stops with them. A diesel fed petrol generally starts, idles and drives away as though nothing has happened, whilst the pump grinds. Fine and running are not the same thing.
Myth: a two-stroke additive makes it safe to drive home. It was an old workaround, supposed for another fault. The petrol is still in your tank after that, and what it has thinned is not put back.
"Drain it yourself and you're sorted" — a myth, because after it has been running some petrol lies in the filter and lines, waiting to go straight back through your pump at your next start. Besides, petrol emptied into a can by the road is genuinely risky.
How petrol ends up: petrol in a diesel
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 generally 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 happens. A new motor, a hire car or a courtesy car. One petrol and one diesel on the driveway of the same household. Your usual forecourt, its pumps suddenly in a different order. A hurried fill en route to Harrow-on-the-Hill with a train to catch. Years of petrol motors behind you, a diesel Renault Megane in front of you at the forecourt for its first tank — that's when. Throw in rain, a phone call or a back seat full of children, and your hand does what it has always done.
Next time you fill up in Roxeth: preventing petrol in a diesel
- Green for unleaded and black for diesel is normal in the UK — yet not on every forecourt. Trust the label on the pump, not the colour.
- Many vehicles state the fuel type inside your filler flap or on the cap, and so check it on the first fill in any vehicle you don't know.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of intending to remember, for a household with one of each.
- "Diesel", aloud, before you pick up the nozzle — every time a new or hired car gets its first tank. It seems daft. It works.
- Mistakes like this are straightforward to make while your mind is on something else, and so the phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to reject a petrol nozzle, and add-on devices exist for motors without one. They are a backstop, not a reason to stop reading the petrol pump.
- Stop as soon as you realise. Less petrol inside the tank makes a thinner mixture. It doesn't change what to do next, which is still not to start the vehicle.
Put petrol in a diesel in Roxeth already?
Short and simple, then, is the order of things. Starting it is out, and so is switching on the ignition. The attendants at the forecourt — whether at Shell itself or wherever you filled up — will normally help roll it clear of the petrol pump if you ask. Ring 0333 366 0103 next, with three facts — your fuel, the rough volume, and whether it has run.
If it was AdBlue instead of petrol, say so. That is a different fault — corrosion and deposits rather than lost protection — and it has its own page for Roxeth.
Why one petrol in a diesel task in Roxeth costs more than another
The four situations above are four separate tasks, so no single quote for this would be honest. Chiefly, the cost moves with which situation you are in. After that it is the share — how much petrol was put in against how much that tank takes — and then where the vehicle is and whether a van can get to it safely.
That's why we ask three questions before costing rather than after: what got in, how much, and if it's run. Those replies turn a range into a straight figure.
About Roxeth
Roxeth is a suburban area in northwest London, situated approximately 10 miles from the city centre. Roxeth sits at an elevation of around 70 metres, with its residential landscape dominated by flat dwellings. Roxeth is located near several neighbouring communities, including Harrow on the Hill, Harrow, and West Harrow, and is home to a population of around 11,452 people.
Across Greater London and around Roxeth: fuel drain cover
Petrol in diesel calls around Roxeth — part of the HA postcode area — go to vans that likewise cover the places around it, Harrow on the Hill, Harrow and West Harrow included. You need not bring your car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots where we work.
At the pump in Roxeth, still?
No position is better: that is where you now are. Leave it turned off, then ring.