Should You Worry? Petrol in a Diesel Car in Gernon Bushes
If it hasn't been started, you can worry far less than you likely are. Petrol resting in a diesel tank does nothing to the engine till something draws it through the system — your ignition priming your pump, your starter, or driving on its own. So the truthful answer to the first question everyone in Gernon Bushes asks, "have I wrecked it?", is normally no. Petrol in Diesel is who to ring, with the engine kept off, so it stays that way. What petrol actually does to a diesel, how to gauge how far it has gone, and how to keep it from happening again: that's the remainder of this page.
Petrol in a diesel: what does it do to the engine?
Two jobs fall to diesel on its journey through a motor. It burns, and before it ignites it lubricates. What keeps the surfaces inside the high-pressure fuel pump and the injectors from grinding against one another is your diesel flowing through them — they are designed to extremely fine clearances.
The second job petrol doesn't do at all, and the first it does badly. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, leaving a pump running on the mixture to wear itself. It is equally made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the knocking.
Put these 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 issue. Once the pump has been running on that petrol, a mechanical issue has begun: anything shed by a pump that's wearing travels downstream to your injectors with the fuel.
Gernon Bushes, petrol in a diesel: four situations, from mild to major
Filled up, not once started. The best case there can be. Only your tank has petrol in it, and so the job is emptying the tank and flushing the fuel system where your car sits. This situation can only really happen on a forecourt: anywhere else, the vehicle got there by being driven.
Ignition on, or started for a second. Once primed, the fuel system has drawn petrol out of your tank up to the filter and your lines. Still usually easy: drain, flush, and the filter sorted.
A few miles driven, and your pump has spent every one of them working on weakened fuel. How hard the vehicle was driven matters as much as how far, and the work takes in that tank, your lines, the fuel filter and clean fuel through the entire system. The school run to Coopersale and Theydon Garnon Church of England Voluntary Controlled Primary School is one thing. A run as far as Chelmsford, under 15 miles away, is a very different task. So is any mileage on the M11, under a mile from Gernon Bushes, where your engine has been running hard throughout.
It protested, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone lumpy. The fuel is not behaving like diesel any more, and your motor is saying so. Pull up on the spot — on the verge on Houblons Hill, at the kerb, down a side road — and don't move it again. Permanent damage is very rare if a vehicle is stopped quickly, and the drain and flush-through that still come first deal with it.
What Gernon Bushes people get told about petrol in a diesel — and the myths in it
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Nothing is removed by topping up — you are left with a bigger tank, still the same mixture. The assumption behind that guidance — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the reverse holds. Myth: "A modern diesel can cope with a bit of petrol." A current diesel sends its fuel through more precise components at higher pressure, which makes the lubrication count more, not less.
This is the one that fools drivers. Myth: "If it starts and drives, there is no harm done." Feed diesel to a petrol engine and it normally won't run, so the driver stops — and the damage stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually will; meanwhile the pump grinds. Fine and running aren't the same thing.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate issue. None of what petrol weakened is put back by it — and later, that tank still contains the petrol.
"Drain it yourself and you're sorted" — a myth, since after it has been running some petrol lies in the filter and lines, ready to go right back through your pump at the next start. Emptying petrol into a can by the roadside is also really risky.
How it happens: petrol in a diesel
No one does it on purpose, and it's seldom carelessness. A diesel nozzle mostly will not fit a petrol vehicle, yet the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error simple, and only in one direction.
It happens when routine and the vehicle stop matching. A new vehicle, a hire car or a courtesy car. A household with one petrol and one diesel on the drive. A well-known forecourt with the pumps in a different order. Fuelling up in a hurry on the way to Harlow Town, with a train to catch. Years of petrol cars behind you, a diesel Volkswagen Passat in front of you at the forecourt for its first tank — that is when. With rain, a call arriving, or children to deal with, the hand simply does what it has always done.
Next time you fill up around Gernon Bushes: avoiding petrol in a diesel
- Check the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on every forecourt. The label is what matters.
- Many vehicles state the fuel inside your filler flap or on the cap, and so check it on your first fill in a motor you don't know.
- One of each in the home? Mark your key to the diesel — a bright fob, a sticker — because meaning to remember isn't enough.
- It seems silly and it does the trick: on your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol 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.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to reject a petrol nozzle, and add-on devices exist for cars without one. They are a backstop, not a reason to stop reading the petrol pump.
- Less petrol makes a thinner mix, and so stop the moment you notice — while remembering that the next stage is unchanged. It's still not to fire it up.
Put petrol in a diesel around Gernon Bushes already?
Then the order of things is short. Do not start it, and don't switch the ignition on. If you're still on the forecourt — Shell or anywhere else — ask the attendants to help you roll it away from the pump. Next, 0333 366 0103. We'll ask what went in, about how much, and if it's been run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a different problem — Gernon Bushes has a page just for it.
Gernon Bushes petrol in a diesel jobs: why one costs more than another
Four different tasks sit behind the four scenarios above — which is why there's no honest single quote. What moves the cost is mostly which of them you're in. Next it's the proportion — how much petrol went in against how much that tank takes — and then where the car is and whether a technician can get to it safely.
Ahead of any quote, not after, come three questions: your fuel that was put in, the quantity, and if it has run. That's why. A range turns into a straight figure when the answers are in.
About Gernon Bushes itself
Gernon Bushes is a locality in Essex, situated inland at an elevation of 109 metres, and is located near Coopersale Common, Coopersale, and Coopersale Street. Gernon Bushes has a population of approximately 862 residents, who mostly reside in semi-detached housing. Gernon Bushes is positioned relatively close to major urban centres, being 17.5 miles from London and 14.8 miles from Chelmsford.
Fuel drain cover across Essex, Gernon Bushes included
Gernon Bushes waits in the CM postcode area, and the teams that answer petrol in diesel jobs there work the places around it as well — Coopersale Common, Coopersale and Coopersale Street among them. A forecourt, a supermarket car park, a lay-by or your own drive are all spots our engineers drain, and the car doesn't need to come to us.
Still at the pump around Gernon Bushes?
The best spot there is, then — that is where you are. Keep the vehicle turned off, then ring.