Boultham Moor: Petrol in a Diesel Car? How Worried to Be
Provided it hasn't been started, worry less than you likely are. Till your ignition primes the pump, your starter turns, or your vehicle is driven, petrol in a diesel tank just sits there and does nothing. Which means the truthful reply to the first Boultham Moor question — "have I wrecked it?" — usually no. Leave the engine off then ring Petrol in Diesel — that is how you keep it that way. The rest of this page explains what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you a second time.
What petrol in a diesel does to your engine
Passing through an engine, diesel is doing two things at the same time. Before it combusts, it lubricates — and then it ignites. Designed to very fine tolerances, the injectors and your pump rely on the diesel moving through them to keep their surfaces from wearing against one another.
Petrol handles the first job badly and the second not at all. A pump working on a petrol mix is wearing itself out, since petrol is runnier than diesel and takes away the lubrication your fuel system depends on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that is where any rattling starts.
The shape of the trouble is plain once you put those together. It is circulation that causes the harm, not contact. Petrol in a tank is a fuel fault. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with the fuel to your injectors downstream.
Four scenarios we see in Boultham Moor: how bad is petrol in a diesel?
Filled up, and never started: nothing beats it. Just the tank has petrol in it, so the task is clearing that tank and cleaning your system where your car sits. This scenario can only really occur at a forecourt: anywhere else, the vehicle got there by being driven.
Ignition on, or started for a second. With your system primed, the lines and filter already contain petrol that came from the tank. That is generally still a straightforward job — a drain, a flush, and your filter dealt with.
A couple of miles driven, and your pump has spent each of them working on thinned fuel. Tank, lines, filter, then fresh fuel put through the entire circuit: that's this work, and the way your car was driven counts as much as the miles. Short trips, such as the school run to Hartsholme Academy, are one matter. Any distance on the M180, under 25 miles from Boultham Moor, means your engine has worked hard throughout, and a run to Lincoln, under 3 miles away, is a very different job too.
Rattling, a ragged idle, smoke, a throttle gone soft: driven until it complained. The fuel isn't behaving like diesel any more, and your engine is saying so. Stop wherever you are — the verge on Westwick Drive, a lay-by, a side street — and leave the car there. Lasting damage is very rare when a car is stopped quickly, and the fuel drain and flush that still come first sort it out.
Myths Boultham Moor motorists hear about petrol in a diesel
False: topping up to full with diesel makes it fine. It doesn't. Topping up removes nothing; it gives you a fuller tank of the same mixture. The assumption behind the advice — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the opposite holds. Myth: "A modern diesel can cope with a bit of petrol." Protection matters more on modern diesels, not less, because their fuel runs through smaller components at higher pressure.
"It starts, it drives, so no harm done" — the myth that catches most drivers than any other. Feed diesel to a petrol motor and it usually won't run, so the driver stops — and the damage stops with them. Feed petrol to a diesel and it usually starts, idles and drives away as if nothing has happened — all the while its pump wears. Fine and running aren't the same at all.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a different issue. It does not put back what petrol has diluted, and that petrol is still in that tank later on.
"Drain it yourself and you're sorted" — a myth, since after it's been running some petrol sits in the filter and lines, waiting to go right back through your pump on your next start. Besides, petrol cleared into a can by the road is truly hazardous.
Why petrol in a diesel occurs so easily
It is rarely carelessness, and no one does it on purpose. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol car at all. The forecourt makes it easy, and the error runs one way.
Routine and your car getting out of step is when it happens. Hire cars, courtesy cars, and vehicles that are new to you. Households running one of each, petrol and diesel. The pumps in a different order on a familiar forecourt. A rushed fill en route to Hykeham with a train to catch. Exactly the moment it happens: after years of driving petrol, someone fills a diesel Peugeot 308 for the first time. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of children.
How to prevent petrol in a diesel on your next fill-up in Boultham Moor
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most usually do. Check the petrol pump's label; the colour is only a hint.
- Plenty of motors state the fuel inside your filler flap or on the cap, and so check it on the first fill in a vehicle you don't know.
- Label your 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 meaning to remember.
- "Diesel", aloud, before you pick up the nozzle — each time a new or hired car gets its first tank. It sounds silly. It does the trick.
- Mistakes like this are easy to make while your mind is on something else, and so your phone goes away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to reject a petrol nozzle, and add-on devices are available for the remainder. Treat it as a backstop, and keep checking the pump.
- Stop as soon as you realise. Less petrol in that tank makes a weaker mix. It does not change what to do next, which is still not to start the vehicle.
Put petrol in a diesel in Boultham Moor already?
Short and simple, then, is the order of things. Leave it unstarted, with your ignition switched off too. Ask the staff to help you roll it clear of the pump if you're still at the forecourt, whether that's Sainsbury's or anywhere else. Then call 0333 366 0103 and tell us what was put in, roughly how much, and whether it's run.
If it was AdBlue rather than petrol, say so. That's a different fault — corrosion and deposits rather than lost lubrication — and it has its own page for Boultham Moor.
What makes one Boultham Moor petrol in a diesel job cost more than the next
The four scenarios above are four separate tasks, so no single quote for this would be honest. Chiefly, the cost moves with which situation you are in. Beyond that it's the proportion — how much petrol was put in against how much the tank takes — and after that where the vehicle is and whether a technician can reach it safely.
Before any quote, not after, come three queries: your fuel that got in, the volume, and if it's run. That's why. Their answers are what change a range into one firm number.
About Boultham Moor
Boultham Moor is a suburban area located on the outskirts of Lincoln, situated near the River Witham in Lincolnshire. Boultham Moor sits at a low elevation of around 12 metres, close to the city centre and nearby places such as Boultham and Swallow Beck. Boultham Moor is characterised by its semi-detached housing and residential community, with easy access to the amenities of Lincoln. Boultham Moor is also relatively close to major cities, with London approximately 119 miles to the south.
Fuel drain cover across Lincolnshire, Boultham Moor included
Boultham Moor waits in the LN postcode area, and our vans that answer petrol in diesel calls there work the spots around it as well — Boultham, Swallow Beck and Bracebridge among them. A forecourt, a supermarket car park, a lay-by or your own drive are all spots our engineers work, and the vehicle doesn't need to move to us.
In Boultham Moor and still at the pump?
Then you're in the best place there is. Keep it off. Call.