How Worried Should You Be? Petrol in a Diesel Car in Highworth
Less than you probably are, if it has not been started. Until your ignition primes your pump, the starter turns, or the car is driven, petrol in a diesel tank simply rests there and does no harm. Which makes the honest reply to the first Highworth query — "have I wrecked it?" — usually no. Keep it like that: leave your engine off then ring Petrol in Diesel. Keep reading for three things: the effect petrol has inside a diesel motor, the signs of how far it has spread, and ways to make sure you don't repeat it.
Inside your engine: what petrol in a diesel really does
Two jobs fall to diesel on its journey round a motor. Lubricating comes before burning; it does both. Designed to extremely fine gaps, the fuel injectors and the pump depend on your diesel flowing through them to stop their surfaces wearing against one another.
Poorly at the first, not at all at the second: that's petrol. Being less viscous than diesel, petrol strips away the protection a fuel system needs, leaving a pump on that mixture to wear itself. It's equally made to resist igniting under compression — the opposite of what a diesel needs — which is why you get the clattering.
Combined, those leave the shape of the problem clear. Not contact but movement is what causes the damage. Petrol in a tank is a fuel fault. After the pump has been running on that petrol, a mechanical issue has started: anything shed by a pump that is wearing down is carried downstream to the fuel injectors with your fuel.
How serious is petrol in a diesel? Four situations our technicians see in Highworth
Filled up, and not started: nothing beats it. Only that tank has petrol in it, so the task is draining that tank and cleaning your system where the car stands. This scenario can only really take place on a forecourt: anywhere else, your car got there by being driven.
Ignition on, or started for a second. The system has been primed, so petrol has left the tank and got to the filter and your lines. Normally nothing more than draining, rinsing and seeing to the fuel filter, so still straightforward.
A few miles driven, and your pump has spent each of them working on diluted fuel. Distance is only half of it; how hard it was driven counts just as much. Either way the work runs to your tank, the lines, the filter and clean fuel through the whole system. Short trips, such as the school run to Southfield Junior School, are one matter. A run as far as Oxford, under 25 miles away, is a very different task. So is any distance on the M4, under 10 miles from Highworth, where your engine has been running hard throughout.
It protested, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone lumpy. What you are hearing is your engine signalling fuel that no longer runs like diesel. Stop on the spot — on the verge on High Street, at the kerb, down a side road — and do not move it. Long-term damage is very rare if a car is pulled over early, and the fuel drain and flush that still come first deal with it.
Highworth motorists and the petrol in a diesel stories they hear
"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 holds more of the same mixture. The assumption behind that advice — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the reverse is true. Myth: "A current diesel can cope with a bit of petrol." Protection matters more on current diesels, not less, since their fuel runs through smaller components at higher pressure.
This is the one that catches motorists. Myth: "If it starts and drives, there is no harm done." The driver of a petrol motor fed diesel normally stops, since it will not run, and the harm stops with them. A diesel fed petrol normally starts, ticks over and drives away as though nothing has happened, whilst your pump grinds. Being able to run isn't the same as being fine.
An old workaround for a different fault lies behind this one. Myth: "Add some two-stroke oil and drive it home." None of what petrol thinned is put back by it — and afterwards, that tank still contains that petrol.
Myth: "Drain the tank yourself and you're sorted." After your engine has run, some of the petrol is no longer in the tank: it is in your filter and your lines, and it goes right back through your pump on your next start. It's also truly risky to drain petrol into a can by the kerbside.
How does petrol in a diesel occur?
Carelessness is seldom the cause, and nobody means to do it. A diesel nozzle generally won't fit a petrol motor, yet the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake straightforward, and just in one direction.
The moment habit stops matching the car is the moment it occurs. Courtesy car, hire car, or a car that is new. A household with one petrol and one diesel on the driveway. Your ordinary forecourt, its pumps suddenly in a different order. Fuelling up in a hurry on the way to Swindon, with a train to catch. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that is when. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of kids.
How to prevent petrol in a diesel on your next fill-up around Highworth
- Read the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, but not on every forecourt. The label is what matters.
- Plenty of vehicles state the fuel type inside the filler flap or on the cap, so check there on your first fill in any motor you don't know.
- Mark the key. In a household with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- Before the nozzle comes off the pump the first time you fill a hired or new motor, say "diesel" aloud. Silly, yes, yet it does the trick.
- While you are thinking about something else, this is an easy mistake to make — so put the phone away.
- Some diesels have a filler built to refuse a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump.
- Stop the moment you realise. Less petrol in your tank means a thinner blend. It does not change what to do next, which is still not to start it.
Already put petrol in a diesel in Highworth?
Then the order of things is short. Don't switch the ignition on, and don't crank it. Yet on the forecourt, at Shell or anywhere else? Ask the staff to help you roll the car away from the pump. Then phone 0333 366 0103 and tell us what went in, about how much, and whether it's run.
If it was AdBlue instead of petrol, say so. That's a separate fault — corrosion and deposits and not lost protection — and it has its own page for Highworth.
Why one petrol in a diesel job in Highworth costs more than another
A fair single price does not exist here: four situations, four separate tasks. Which of them you're in is chiefly what moves your cost. Two things follow that: the petrol that was put in as a proportion of what your tank holds, then the spot your car is in and whether a van can get to it safely.
That's why we ask three questions before quoting instead of after: what went in, how much, and if it has run. Those answers change a range into a straight figure.
About Highworth itself
Highworth is a town in north Wiltshire, situated in the inland countryside at an elevation of around 136 metres. Highworth lies near the villages of Westrop and Eastrop, and is also close to the residential area of Redlands. Highworth is characterized by its predominantly detached housing stock, and is located approximately 21 miles from Oxford and 69 miles from London.
Highworth and Wiltshire: where our fuel drain cover runs
Petrol in diesel jobs in Highworth — part of the SN postcode area — go to teams that likewise cover the spots about it, Westrop, Eastrop and Redlands among them. You need not bring the car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations we drain.
Highworth: still at the petrol pump?
Then you're in the best position there can be. Ring, and keep it turned off.