How Worried Should You Be? Petrol in a Diesel Car in Lowton Heath
Not started? Then less anxious than you probably are. "Have I ruined it?" is the first question anyone around Lowton Heath asks, and the honest answer is generally no, since petrol left in a diesel tank hurts nothing till it's drawn through the fuel system — by ignition priming, by the starter, or by driving. Leave your motor off then ring Petrol in Diesel — that is how you keep it like that. The rest of this page sets out what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you again.
What petrol in a diesel does to your engine
Two tasks fall to diesel on its route through a motor. It ignites, and before it combusts it lubricates. Built to very fine tolerances, your injectors and the pump depend on your diesel moving through them to stop their surfaces wearing against one another.
Poorly at the first, not at all at the second: that's petrol. It is thinner than diesel and strips away the lubrication the system depends on, and so a pump running on a petrol blend is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That is where the knocking comes from.
Put those together and the shape of the problem is plain. The damage is done by circulation, not by contact. All a tank with petrol in it amounts to is a fuel problem. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to your injectors downstream.
How serious is petrol in a diesel? Four scenarios our engineers see around Lowton Heath
Filled but not once started — as good as it gets. Being at a forecourt is what makes this the case: elsewhere, your car has been driven there to begin with. With the petrol held in your tank alone, it's drained and cleaned right where it stands, and nothing more is needed.
Started for a moment, or only the ignition on. Once primed, your system has pulled petrol out of your tank as far as your filter and the lines. Drain, flush, deal with your filter: still normally straightforward.
A couple of miles driven, and the pump has spent every one of them working on diluted fuel. The work is your tank, your lines, your filter and fresh fuel through the whole system, and how hard the car was driven matters as much as how far. Short trips, like the school run to St Luke's CofE Primary School, are one matter. Very different again: a run to Salford, under 15 miles away, or some miles on the M6, under a mile from Lowton Heath, where the motor kept labouring hard.
Rattling, an uneven idle, smoke, a throttle gone soft: driven until it complained. The fuel isn't behaving like diesel any more, and your motor is saying so. Pull up wherever you are — the verge on Grange Close, a lay-by, a side street — and leave the car where it is. What comes first is still the fuel drain and flush, and that sorts it out, with lasting damage very unusual if a vehicle is pulled over quickly.
What Lowton Heath people get told about petrol in a diesel — and the stories in it
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. A bigger tank of the same mixture is all it gives, because topping up takes out nothing. That guidance supposes a diesel fuel system handles petrol by percentage. It doesn't.
If anything, the opposite is true. Myth: "A newer diesel can cope with a bit of petrol." A newer diesel runs its fuel through more precise components at higher pressure, which makes the protection count more, not less.
This is the one that fools motorists. Myth: "If it starts and drives, there's no damage done." Any petrol motor fed diesel normally won't run, so the driver stops and the damage stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile your pump grinds. Fine and running aren't the same at all.
An outdated fix for a separate fault lies behind this one. Myth: "Add some two-stroke oil and drive the car home." That petrol is still inside your tank after that, and what it has diluted isn't put back.
The next start sends petrol back round your pump from the fuel lines and the fuel filter, where some of it sits after the motor has run. That is why draining the tank yourself does not sort it — a myth. It is also truly hazardous to drain petrol into a can at the roadside.
Why petrol in a diesel takes place so easily
A careless moment is seldom the cause, and nobody means to do it. One way only, because of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, whereas the diesel one generally will not fit a petrol motor. That is how the forecourt makes it straightforward.
Habit and the car getting out of step is when it occurs. Any motor that's new to you — a hire car, on loan as a courtesy car, or just bought. One petrol and one diesel on the drive of the same household. A familiar forecourt with the pumps in a different order. A train to catch, and a rushed fill on the way to Newton-Le-Willows. Years of petrol cars behind you, a diesel Renault Megane in front of you on the forecourt for its first tank — that is when. Throw in a back seat full of children, a phone call or rain, and habit takes over.
Next time you fill up in Lowton Heath: avoiding petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most usually do. Read the petrol pump's label; the colour is only a hint.
- Plenty of motors state the fuel inside the filler flap or on the cap, and so check it on the first fill in a vehicle you do not know.
- Good intentions count for less than a sticker or a fob in a bright colour on your diesel's key if a house has one of each. So mark it.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It sounds daft and it does the trick.
- Put the phone away. This is an easy mistake to make while you're thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to refuse a petrol nozzle, and add-on devices exist for vehicles without one. They are a backstop, not a reason to stop reading the petrol pump.
- Stop as soon as you realise. Less petrol in that tank means a weaker mixture. It doesn't change what to do next, which is still not to start it.
Petrol already in a diesel in Lowton Heath? Begin here
The order of things is short, then. Do not switch the ignition on, and do not fire it up. The attendants on the forecourt — whether at Esso itself or wherever you filled up — will usually help roll it away from the petrol pump if you ask. Next, 0333 366 0103. We'll ask what went in, roughly how much, and if it's been run.
Say so if it was AdBlue rather than petrol: it's a different issue, with its own page for Lowton Heath, since AdBlue brings corrosion and deposits instead of lost lubrication.
What makes one Lowton Heath petrol in a diesel job cost more than the next
An honest single price does not exist here: four scenarios, four separate jobs. What shifts your cost is chiefly which of them you are in. The proportion matters next, meaning how much of that tank is petrol, and then the location of your car and whether reaching it is safe for a technician.
That is why our engineers ask three queries before costing rather than after: what got in, how much, and if it's run. Those replies change a range into a straight figure.
About Lowton Heath
Lowton Heath is a small hamlet situated on the riverside in Greater Manchester, with an elevation of around 36 metres. Lowton Heath lies near the town of Lowton and other nearby places such as Lane Head and Bank Heath. Lowton Heath is characterized by its predominantly detached housing stock, reflecting its relatively rural setting within the North West region. Lowton Heath is located approximately 12 miles from the city of Salford and about 170 miles from London.
Across Greater Manchester and in Lowton Heath: fuel drain cover
Town of Lowton, Lane Head and Bank Heath are among the places around Lowton Heath that the same vans work, answering petrol in diesel jobs across Lowton Heath's WA postcode area. The vehicle doesn't need to move to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
At the pump around Lowton Heath, still?
Then you are in the best position there can be. Switched off it remains; then call.