How Worried Should You Be? Petrol in a Diesel Car in Forder
Provided it has not been started, you can worry less than you probably are. Until your ignition primes your pump, the starter cranks, or your vehicle is driven, petrol in a diesel tank just waits there and does nothing. Which makes the truthful reply to the first Forder question — "have I ruined it?" — usually no. Leave the engine off and call Petrol in Diesel — that keeps it that way. What petrol really does to a diesel, how to gauge how far it's travelled, and how to keep it from happening again: that's the rest of this page.
Petrol in a diesel: what does it do to the engine?
Diesel has two tasks on its way through a motor. It lubricates first, and only then does it burn. Very fine gaps are built into the fuel injectors and the high-pressure pump, and just your diesel flowing through stops those surfaces grinding together.
Poorly at the first, not at all at the second: that's petrol. The knocking comes from petrol being made not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips out the protection the fuel system depends on, and any pump working on such a mix is wearing itself.
Put these together and the shape of the trouble is clear. The harm is done by circulation, not by contact. All a tank with petrol in it amounts to is a fuel problem. Once the pump has been running on that petrol, a mechanical fault has started: anything shed by a pump that is wearing down is carried downstream to your injectors with the fuel.
Petrol in a diesel around Forder: how serious is it? Four cases
Fuelled, and not started: nothing beats it. At a forecourt, and truly only there, that petrol is still confined to your tank — since everywhere else your car was driven to reach it. The job is emptying and cleaning on the spot.
A brief spell of running, or just the ignition on. With your system primed, your lines and filter now hold petrol that has come from the tank. Normally nothing more than emptying, rinsing and sorting the filter, and so still simple.
Your pump has spent a few miles on thinned fuel — that's what driving the vehicle meant. The work is the tank, the lines, the fuel filter and fresh fuel through the whole circuit, and how hard the vehicle was driven counts as much as how far. Short trips, such as the school run to St Stephens (Saltash) Community Primary School & Nursery, are one thing. A run as far as Plymouth, under 5 miles away, is a very different task. So is any miles on the M5, under 50 miles from Forder, where the motor has been labouring hard the whole time.
Driven on till it complained — rattling, smoke, an uneven idle, a soft throttle. That's your motor telling you its fuel has stopped behaving like diesel. Whether it is the verge on Castle Hill, a lay-by or a side street, stop there then leave it. The drain and flush still come first, and they deal with it: when a car is pulled over quickly, permanent damage is very uncommon.
What Forder people get told about petrol in a diesel — and the stories in it
Myth: topping up to full with diesel makes it fine. It does not. Topping up takes out nothing; it gives you a fuller tank of the same mix. Percentage isn't how a diesel fuel system copes with petrol, whatever that advice presumes.
If anything, the opposite is true. Myth: "A newer diesel can cope with a bit of petrol." A modern diesel runs its fuel through finer components at higher pressure, which makes the lubrication count more, not less.
Myth: "If it starts and drives, there's no harm done." This is the one that catches motorists. Diesel in a petrol motor normally means a motor that won't run: the motorist stops, and so does the harm. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile the pump wears. Running isn't the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a distinct fault. None of what petrol diluted gets put back by it — and afterwards, your tank still holds that petrol.
Myth: "Drain that tank yourself and you're sorted." Once the motor has run, some of the petrol is no longer inside the tank: it's in the filter and the fuel lines, and it goes straight back through the pump on the next start. It is also really hazardous to drain petrol into a can at the kerbside.
How does petrol in a diesel take place?
On purpose? Never. Through carelessness? Rarely, if ever. The forecourt makes it easy: the petrol nozzle is the narrower of the two, and it slides into a diesel filler with almost no resistance, whilst a diesel nozzle generally won't go into a petrol vehicle at all. So the error runs one way.
When habit and your car stop matching, it occurs. Courtesy car, hire car, or a vehicle that's brand new. Households running one of each, petrol and diesel. A familiar forecourt with the pumps in a different order. A train to catch, and a hurried fill on the way to Saltash. Years of petrol motors behind you, a diesel Renault Megane in front of you at the forecourt for its first tank — that is when. Add a back seat full of kids, a phone call or rain, and habit wins.
Forder drivers: how to avoid petrol in a diesel next time
- The label is what matters, so check the petrol pump instead of the colour: in the UK unleaded handles are usually green and diesel black, yet not on every forecourt.
- In a car you don't know, look inside the flap over your filler or at the cap before the first fill: plenty of vehicles print the fuel type there.
- Label the key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- It seems silly and it does the trick: on the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck your phone away then keep your mind on the pump.
- Some diesels come with a filler designed to refuse a petrol nozzle, and devices you can add exist for cars without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the petrol pump.
- The moment you notice, stop: less petrol in that tank makes a weaker mixture. What to do next doesn't change, though — still don't start the vehicle.
Put petrol in a diesel around Forder already?
Then, there's just a short order of things. Starting it is out, and so is turning on your ignition. Still on the forecourt, at Shell or anywhere else? Ask the attendants to help you push the car clear of the pump. Next, 0333 366 0103. We'll ask what was put in, roughly how much, and if it's been run.
Say so if it was AdBlue rather than petrol: it's a different problem, with its own page for Forder, because AdBlue brings corrosion and deposits rather than lost protection.
Why one petrol in a diesel job around Forder costs more than another
Four separate tasks lie behind the four situations above — which is why there's no honest single price. Which of them you are in is chiefly what moves the cost. The share matters next, meaning how much of that tank is petrol, followed by the location of your car and whether getting to it is safe for our van.
What got in, how much, and if it's run — three questions our engineers ask before pricing, not after, for exactly that reason. Given those answers, there is a straight figure instead of a range.
About Forder, for a moment
Forder is a small coastal village in Cornwall, situated near the city of Plymouth and overlooking the sea at an elevation of around 9 metres. Forder has a mix of housing types, but terraced homes are particularly prevalent, reflecting the village's history of development. Forder is close to several notable nearby places, including St Stephens, Trematon Castle, and Burraton Coombe. Forder remains a relatively small community, with a population of approximately 945 residents.
Fuel drain cover across Cornwall, Forder included
Forder rests in the PL postcode area, and the vans that answer petrol in diesel jobs there work the locations near it as well — St Stephens, Trematon Castle and Burraton Coombe among them. The car doesn't need to come to us: we drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
In Forder and still at the pump?
The best place there is, then — that's where you are. Turned off it remains; then call.