Strood: Petrol in a Diesel Car? How Worried to Be
Likely less than you already are — provided no one has started it. "Have I ruined it?" is the first thing anyone around Strood asks, and the honest answer is normally no, since petrol left in a diesel tank harms nothing until it's drawn through your fuel system — by ignition priming, by the starter, or by driving. Leave your motor off then phone Petrol in Diesel — that keeps it that way. The rest of this page explains 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.
What petrol in a diesel does to your engine
Passing through a motor, diesel is doing two jobs at the same time. Before it burns, it protects — then it burns. What stops the surfaces inside the high-pressure pump and your injectors from wearing against one another is the diesel passing through them — they are made to extremely fine tolerances.
Badly at the first, not at all at the second: that's petrol. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, so a pump running on the blend wearing itself. It's equally made to resist igniting under compression — the reverse of what a diesel needs — which is why you get the clattering.
The shape of the issue is clear once you put those together. Not contact but circulation is what does the harm. A tank with petrol in it is a fuel issue. A pump that has been labouring on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with the fuel to the injectors further on.
Petrol in a diesel around Strood: how serious is it? Four cases
Fuelled, and never started: nothing beats it. Only the tank has petrol in it, and so the job is draining the tank and cleaning the fuel system where the car stands. This situation can only really take place at a forecourt: anywhere else, the car got there by being driven.
Started for a second, or only the ignition on. The system has been bled, so petrol has left your tank and got to the fuel filter and the lines. Usually little more than draining, rinsing and sorting your filter, so still easy.
Some miles driven, and the pump has spent every one of them running on weakened fuel. How hard the vehicle was driven counts as much as how far, and this work takes in your tank, the lines, the fuel filter and fresh fuel through the entire system. Short trips, such as the school run to All Faiths Children's Academy, are one thing. Any distance on the M2, under 3 miles from Strood, means the motor has worked hard throughout, and a run to Southend-on-Sea, under 15 miles away, is a very different task too.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. That's the motor telling you its fuel no longer is behaving like diesel. Whether it is the verge on High Street, a lay-by or a side street, stop there and leave it. Lasting damage is very uncommon when a car is stopped soon, and the fuel drain and flush that still go first sort it out.
What Strood drivers get told about petrol in a diesel — and the myths in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Topping up removes nothing; it gives you a fuller tank of the same mixture. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance supposes.
"Newer diesels can handle a little petrol" — a myth, and nearer the reverse. More precise components and higher pressure are the way a modern diesel runs its fuel, and that makes the lubrication count more, not less.
"It starts, it drives, and so no harm done" — the myth that trips up most drivers than any other. The motorist of a petrol engine fed diesel normally has no choice but to stop, because it will not run, and the damage stops with them. Feed petrol to a diesel and it normally starts, ticks over and pulls away as if nothing has happened — all the while its pump wears. Fine and running are not the same at all.
Not so: a two-stroke additive makes it safe to drive home. It was an old fix, meant for another issue. What petrol has diluted remains weakened, and the petrol stays inside your tank regardless.
The next start sends petrol back round the pump from your lines and the fuel filter, where some of that ends up after the engine has run. That's why draining your tank yourself does not sort it — a myth. It's also truly dangerous to drain petrol into a can at the roadside.
Why petrol in a diesel takes place so easily
A careless moment is rarely the cause, and no one means to do it. One way only, because of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, while the diesel one generally won't fit a petrol motor. That is how the forecourt makes it easy.
Routine and the car getting out of step is when it happens. Any motor that is new to you — a hire car, on loan as a courtesy car, or brand new. One petrol and one diesel on the driveway of the same household. Your usual forecourt, its pumps now in a different order. Filling up in a hurry en route to the nearest station, with a train to catch. A new-to-you diesel Renault Megane, its first fuelling, and a motorist used to petrol: exactly when it occurs. Your hand repeats what it has always done once you add rain, a phone call or a back seat full of kids.
Strood motorists: how to prevent petrol in a diesel next time
- Read the petrol pump, not the colour. In the UK unleaded handles are normally green and diesel black, yet not on each forecourt. The label is what matters.
- Plenty of motors state the fuel inside the filler flap or on the cap, so check there on the first fill in a car you don't know.
- Label your 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 the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the petrol pump. It sounds silly and it does the trick.
- Mistakes like this are straightforward to make whilst your mind is on something else, and so the phone goes away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to refuse a petrol nozzle, and aftermarket devices are available for the remainder. Count it as a safety net, and keep reading the pump.
- Noticing it mid-fill? Stop there and then. A thinner mix follows from less petrol in that tank, but your next stage stays the same: don't fire it up.
Put petrol in a diesel around Strood already?
The order of things is brief, then. Don't turn your ignition on, and don't fire it up. The attendants on the forecourt — whether at Texaco itself or wherever you filled up — will normally help roll it clear of the petrol pump if you ask. What was put in, roughly how much, and whether it's run: tell us those when you call 0333 366 0103.
If it was AdBlue instead of petrol, say so. That's a separate fault — corrosion and deposits and not lost lubrication — and it has its own page for Strood.
Why one petrol in a diesel job around Strood costs more than another
An honest single price doesn't exist here: four situations, four separate tasks. Mostly, your cost shifts with which situation you are in. Where the vehicle is counts too, and whether a technician can safely get to it, after the share of petrol to what the tank holds.
What went in, how much, and if it has run — three questions we ask before pricing, not after, for exactly that reason. Those answers are what turn a range into one firm number.
About Strood
Strood is a suburban area in Kent, situated on the coast of the Thames Estuary at an elevation of 29 metres. Strood lies near the historic city of Rochester and the village of Frindsbury, and is connected to surrounding areas by road and rail links. Strood has a mix of housing types, but is predominantly characterised by terraced homes. Strood is also close to other nearby places, including Troy Town and the city of Southend-on-Sea, which is 13.6 miles away.
Strood and Kent: where our fuel drain cover reaches
Frindsbury, Rochester and Troy Town are among the locations near Strood that the same teams work, answering petrol in diesel calls across Strood's ME postcode area. No need to move the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all places where we work.
Strood: still at the petrol pump?
Then you're in the best place there can be. Keep it off. Call.