Shawhead: Petrol in a Diesel Car? How Worried to Be
Likely less than you are now — provided nobody has started the vehicle. Until your ignition primes the pump, your starter cranks, or the car is driven, petrol in a diesel tank just waits there and does nothing. Which makes the truthful reply to that first Shawhead query — "have I ruined it?" — usually no. Petrol in Diesel is who to phone, with the engine kept off, and so it stays that way. The remainder of this page covers what petrol really does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you again.
Your engine and petrol in a diesel: what happens
On its way through an engine, diesel does two jobs. It ignites, and before it ignites it lubricates. Made to very fine tolerances, your injectors and your pump rely on your diesel flowing through them to keep their surfaces from wearing against one another.
Petrol does the first job poorly and the second not at all. The clattering comes from petrol being designed not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips out the protection your system hinges on, and any pump working on that mixture is wearing itself.
Put these together and the shape of the trouble is plain. Contact does not do the harm — movement does. Petrol in a tank is a fuel problem. The start of a mechanical problem is a pump that has been working on that petrol — and whatever a worn pump sheds moves on with the fuel to your injectors beyond it.
Four situations our technicians see around Shawhead: how bad is petrol in a diesel?
Fuelled, and never started: nothing beats it. Being on a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With the petrol held inside that tank alone, it's drained and rinsed right where it stands, and nothing more is needed.
Started for a second, or just the ignition on. With the system primed, the lines and filter now hold petrol that has come from your tank. That's usually still a simple task — a drain, a flush, and the filter dealt with.
Driven a couple of miles. Now the pump has spent these miles running on diluted fuel. The work is the tank, your lines, your filter and fresh fuel through the entire system, and how hard the car was driven matters as much as how far. Driving the children to the local primary school is one sort of trip. Any miles on the M8, under a mile from Shawhead, means your engine working hard throughout, and a run to Glasgow, under 10 miles away, is a very different task too.
Clattering, an uneven idle, smoke, a throttle gone soft: driven till it complained. What you are hearing is your motor reporting fuel that no longer runs like diesel. Whether it is the verge on Rose Gardens, a lay-by or a side street, stop where you are then leave it. A car stopped early very rarely has lasting damage, since the fuel drain and the flush, which still go first, take care of it.
Shawhead drivers and the petrol in a diesel myths they hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing is removed by topping up — you're left with a fuller tank, still the same mix. A diesel fuel system doesn't accept petrol by percentage in the way that guidance assumes.
"Modern diesels can handle a little petrol" — a myth, and nearer the reverse. At higher pressure, through finer components: that is how a newer diesel moves its fuel, so the protection matters for more, not less.
The myth that catches drivers out: if it starts and drives, it must be unharmed. A petrol engine fed diesel normally will not run, and so the driver stops and the damage stops with them. Whilst the pump grinds, a diesel fed petrol usually starts, ticks over and drives away as if nothing has happened. Running is not the same as fine.
An outdated fix for a distinct problem is behind this one. Myth: "Add some two-stroke oil and drive it home." It doesn't put back what petrol has weakened, and that petrol is still inside your tank later.
"Drain it yourself and you're sorted" — a myth, since after it has been running some petrol lies in the fuel filter and lines, waiting to go straight back through your pump on the next start. On top of that, petrol emptied into a can by the road is truly dangerous.
Why petrol in a diesel occurs so easily
A careless moment is seldom the cause, and no one means to do it. One way only, because of the nozzles: the smaller petrol one slips inside a diesel filler with almost no resistance, while the diesel one generally won't fit a petrol car. That's how the forecourt makes it simple.
When habit and your car stop matching, it takes place. Hire cars, courtesy cars, and motors that are new to you. A household with one petrol and one diesel on the drive. Your normal forecourt, its pumps now in a different order. Racing for a train at Whifflet and filling up en route. Years of petrol motors behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that is when. With rain, a call arriving, or a car full of children to deal with, the hand just does what it has always done.
Preventing petrol in a diesel next time you fill up in Shawhead
- The label is what matters, and so check the pump instead of the colour: in the UK unleaded handles are normally green and diesel black, but not on each forecourt.
- Many cars state the fuel inside your filler flap or on the cap, and so check there on the first fill in a car you don't know.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of intending to remember, for a household with one of each.
- Before the nozzle comes off the pump the first time you fill a hired or new vehicle, say "diesel" out loud. Daft, yes, but it works.
- Mistakes like this are straightforward to make while your mind is on something else, so your phone goes away.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to refuse a petrol nozzle, and aftermarket devices exist for the rest. Treat it as a safety net, then keep reading the petrol pump.
- Less petrol means a thinner blend, and so stop the moment you realise — though remembering that your next stage is unchanged. It is still not to start it.
Put petrol in a diesel in Shawhead already?
Then the order of things is brief. Leave it unstarted, with the ignition off too. Yet on the forecourt, at Esso or anywhere else? Ask the attendants to help you roll it away from the petrol pump. What went in, roughly how much, and if it has run: tell us those when you phone 0333 366 0103.
If it was AdBlue and not petrol, say so. That's a separate problem — corrosion and deposits and not lost protection — and it has its own page for Shawhead.
Shawhead petrol in a diesel tasks: why one costs more than another
The four scenarios above are four different jobs, so no single quote for this would be honest. What moves your cost is mostly which of them you're in. The proportion counts next, meaning how much of the tank is petrol, followed by the position of your car and whether getting to it is safe for a van.
Before any quote, not after, come three questions: the fuel that went in, its volume, and whether it has run. That's why. Their replies are what change a range into one firm number.
About Shawhead
Shawhead is a suburban area in North Lanarkshire, situated inland at an elevation of 82 metres, approximately 8 miles east of Glasgow. Shawhead is characterized by its predominantly terraced housing stock, reflecting the typical residential architecture of the region. Shawhead is close to nearby places such as Rosehall, Kirkshaw, and Old Monkland, and is home to a population of around 2945 people. Shawhead is located relatively far from London, at a distance of 339 miles.
Shawhead and North Lanarkshire: where our fuel drain cover reaches
Shawhead rests in the ML postcode area, and our vans that answer petrol in diesel calls there work the places around it as well — Rosehall, Kirkshaw and Old Monkland among them. The car doesn't need to come to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
At the petrol pump in Shawhead, still?
No position is better: that's where you now are. Turned off it stays; then ring.