How Worried Should You Be? Petrol in a Diesel Car in Clayhidon
Not started? Then less worried than you likely feel. "Have I ruined it?" is the first question anyone around Clayhidon asks, and the truthful answer is normally no, since petrol resting in a diesel tank harms nothing until it is drawn through the fuel system — by ignition priming, by your starter, or by driving. To leave it that way, call Petrol in Diesel then leave your motor alone. What petrol actually does to a diesel, how to judge how far it's gone, and how to stop it from happening a second time: that is the remainder of this page.
Inside the engine: what petrol in a diesel really does
Diesel does two jobs on its way through an engine. Lubricating comes before burning; it does both. What stops the surfaces inside your high-pressure pump and your injectors from grinding against one another is the diesel flowing through them — they are made to very fine gaps.
Badly at the first, not at all at the second: that is petrol. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, so 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.
The shape of the issue is clear once you put those together. The damage is done by movement, not by contact. Any tank with petrol in it is a fuel problem. Whatever a worn pump sheds goes on, borne by the fuel, into the fuel injectors further along, which is why a pump that has worked on that petrol is where a mechanical issue starts.
Four situations our technicians see in Clayhidon: how serious is petrol in a diesel?
Filled up, and not started: no case is better. Only the tank has petrol in it, so the task is emptying the tank and rinsing your system where the vehicle stands. This scenario can only truly occur on a forecourt: anywhere else, the car got there by being driven.
A brief spell of running, or merely your ignition on. Petrol has left your tank and reached your filter and the lines, since the fuel system has been primed. Usually little more than draining, flushing and seeing to your filter, so still simple.
Driven a few miles. Now your pump has spent these miles working on diluted fuel. Mileage is only half of it; how hard it was driven matters equally. Either way the work runs to that tank, the lines, the filter and fresh fuel through the whole circuit. The school run to Hemyock Primary School is one thing. Very different a second time: a run to Exeter, under 25 miles away, or any mileage on the M5, under 3 miles from Clayhidon, where the motor kept working hard.
Knocking, an uneven idle, smoke, a throttle gone soft: driven until it complained. The motor is telling you your fuel is no longer behaving like diesel. Leave it wherever it has stopped: a lay-by, a side street, the verge on Battle Street. Lasting damage is very unusual if a car is pulled over quickly, and the drain and flush-through that still come first sort it out.
What Clayhidon drivers get told about petrol in a diesel — and the myths in it
False: topping up to full with diesel makes it fine. It doesn't. Nothing is removed by topping up — you're left with a fuller tank, still the same mix. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance assumes.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the opposite. Smaller parts and higher pressure are the way a newer diesel runs its fuel, and that makes the protection count more, not less.
This is the one that fools people. Myth: "If it starts and drives, there's no harm done." The driver of a petrol motor fed diesel usually has no choice but to stop, because it will not run, and the damage stops with them. Feed petrol to a diesel and it usually fires up, idles and pulls away like nothing has happened — all while its pump is wearing. Being able to run isn't proof of being fine.
An outdated fix for a different problem lies behind this one. Myth: "Add some two-stroke oil and drive the car home." That petrol is still in that tank afterwards, and whatever it has thinned isn't put back.
"Drain it yourself and you are sorted" — a myth, since after it's been running some petrol sits in your filter and lines, ready to go right back through the pump on your next start. It is also truly hazardous to drain petrol into a can by the roadside.
Petrol in a diesel: how does it occur?
Carelessness is rarely the cause, and nobody means to do it. The forecourt makes it simple: the petrol nozzle is the smaller of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle mostly will not go into a petrol motor at all. So the mistake runs one way.
Habit and your car falling out of step is when it occurs. Hire cars, courtesy cars, and motors that are new to you. One petrol and one diesel on the driveway of the same household. The pumps in a different order on a familiar forecourt. A train to catch, and a rushed fill on the way to Tiverton Parkway. A new-to-you diesel Skoda Octavia, its first fuelling, and a driver used to petrol: exactly when it takes place. Throw in rain, a phone call or a back seat full of children, and the hand does what it has always done.
Clayhidon motorists: how to prevent petrol in a diesel next time
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most generally do. Read the petrol pump's label; the colour is only a hint.
- Inspect your filler flap. Plenty of motors state the fuel type inside the flap or on the cap. Look at it on your first fill in any vehicle you don't know.
- A coloured fob or a sticker on the diesel's key does more than any amount of intending to remember, in a home with one of each.
- It seems daft and it works: on your first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump.
- Thinking about something else is when this becomes an easy mistake to make, so tuck the phone away and keep your mind on the pump.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to reject a petrol nozzle, and add-on devices exist for motors without one. They are a backstop, not a reason to stop checking the petrol pump.
- Stop the moment you notice. Less petrol inside that tank means a thinner mix. It does not change what to do next, which is still not to crank it.
Put petrol in a diesel in Clayhidon already?
Then, there's only a short order of things. Don't crank it, and don't switch the ignition on. If you are still on the forecourt — Monument Fuels or anywhere else — ask the staff to help you roll the car clear of the petrol pump. Next, 0333 366 0103. We will ask what was put in, roughly how much, and if it has been run.
Say so if it was AdBlue rather than petrol: it's a different problem, with its own page for Clayhidon, since AdBlue brings corrosion and deposits instead of lost lubrication.
Why one petrol in a diesel task around Clayhidon costs more than another
Four different tasks lie behind the four scenarios above — which is why there is no fair single price. What moves the cost is chiefly which of them you are in. Two things follow that: the petrol that went in as a proportion of what the tank takes, then the place the car is in and whether our van can get to it safely.
That is why our technicians ask three queries before quoting rather than after: what got in, how much, and whether it has run. A range turns into a straight figure when the answers are in.
About Clayhidon
Clayhidon is a small hamlet in inland Devon, situated at an elevation of 232 metres, approximately 20.7 miles from Exeter. Clayhidon is characterised by its predominantly detached housing stock, with the hamlet being home to around 508 residents. Clayhidon sits near other local places such as Rosemary Lane, Garlandhayes, and Simonsburrow, in a rural area of the South West region. Clayhidon is located about 138.5 miles west of London.
Clayhidon and Devon: where our fuel drain cover reaches
Petrol in diesel jobs around Clayhidon — part of the EX postcode area — go to teams that also cover the spots around it, Rosemary Lane, Garlandhayes and Simonsburrow among them. The car does not need to come to us: our engineers drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
In Clayhidon and still at the pump?
Then you are in the best place there is. Switched off it remains; then phone.