Petrol in a Diesel Car in Pennywell: How Worried Should You Be?
Unstarted? Then less worried than you probably feel. Till your ignition primes your pump, the starter turns, or your car is driven, petrol in a diesel tank simply waits there and does nothing. Which makes the truthful reply to that first Pennywell query — "have I ruined it?" — normally no. To leave the vehicle that way, ring Petrol in Diesel and leave the motor switched off. Further down, this page sets out what petrol actually does inside a diesel, how far it may have gone, and how to stop it happening to you again.
Inside your engine: what petrol in a diesel does
Two jobs fall to diesel on its route round a motor. Oiling comes before burning; it does both. Designed to very fine tolerances, the fuel injectors and your pump rely on your diesel flowing through them to stop their surfaces wearing against one another.
Petrol does the first task badly and the second not at all. Being less viscous than diesel, petrol strips away the protection a fuel system needs, so a pump on the blend wearing itself. It's equally made to resist igniting under compression — the opposite of what a diesel needs — which is why you hear the rattling.
Seen together, they make clear what shape the trouble has. Not contact but circulation is what causes the damage. A tank with petrol in it is a fuel issue. Once the pump has been running on that petrol, a mechanical problem has started: anything shed by a pump that's grinding travels onward to the fuel injectors with your fuel.
Four scenarios our technicians see in Pennywell: how serious is petrol in a diesel?
The best case there is: filled up, never started. On a forecourt, and genuinely only there, the petrol is still confined to that tank — since everywhere else the car was driven to get to it. The job is emptying and purging on the spot.
Your ignition switched on, or a brief start. The system has been primed, so petrol has left the tank and got to your filter and your lines. That's usually still an easy job — a drain, a flush, and your filter dealt with.
The pump has spent a couple of miles on diluted fuel — that is what driving the car does. How hard your car was driven matters as much as how far, and this work takes in that tank, the fuel lines, the fuel filter and clean fuel through the whole circuit. A school run to St Anne's Roman Catholic Voluntary Aided Primary School is one thing. A run as far as Sunderland, under 3 miles away, is a very different task. So is any distance on the Western Highway, under 5 miles from Pennywell, where the motor has been labouring hard the whole time.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone uneven. What you are hearing is the motor reporting fuel that no longer behaves like diesel. Leave it wherever it has stopped: a lay-by, a side street, the verge on Peasemoor Road. What goes first is still the drain and flush-through, and that takes care of it, with long-term damage very uncommon if a vehicle is pulled over quickly.
Petrol in a diesel myths Pennywell motorists hear
Myth: topping up to full with diesel makes it fine. It doesn't. Topping up takes out nothing; it gives you a bigger tank of the same mix. Percentage isn't how a diesel fuel system copes with petrol, however much that guidance presumes.
"Current diesels can handle a little petrol" — a myth, and nearer the opposite. At higher pressure, through smaller components: that's how a newer diesel moves its fuel, and so the protection matters more, not less.
"It starts, it drives, so there is no harm" — the myth that trips up most people than any other. Any petrol motor fed diesel normally will not run, and so the driver stops and the damage stops with them. While your pump grinds, a diesel fed petrol usually starts, ticks over and drives away as if nothing has happened. Running isn't the same as fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It's an outdated fix for a different problem. It does not put back what petrol has weakened, and the petrol is still inside the tank afterwards.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol lies in your filter and lines, ready to go straight back through the pump at your next start. And, a can of petrol filled at the roadside is truly risky.
How does petrol in a diesel happen?
Nobody does it on purpose, and it's seldom carelessness. A diesel nozzle generally won't fit a petrol motor, yet the narrower petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error easy, and only in one direction.
When habit and the car stop matching, it happens. A new motor, a hire car or a courtesy car. A household with one petrol and one diesel on the drive. The pumps in a different order on a familiar forecourt. Rushing for a train at Sunderland and filling up en route. Years of petrol vehicles behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that is when. Throw in a back seat full of children, a phone call or rain, and the hand wins.
Avoiding petrol in a diesel next time you fill up in Pennywell
- A green handle for unleaded and black for diesel is usual in the UK — yet not on each forecourt. Go by the label on the pump, not the colour.
- In a car you don't know, look inside the flap over your filler or at the cap before your first fill: plenty of cars print the fuel there.
- Good intentions do less than a sticker or a fob in a vivid colour on the diesel's key if a home has one of each. So mark it.
- Before the nozzle leaves the pump the first time you fuel a hired or new motor, say "diesel" aloud. Daft, perhaps, yet it works.
- Thinking about something else is when this becomes an easy mistake to make, so put your phone away then keep your mind on the petrol pump.
- Some diesels have a filler designed to block a petrol nozzle, and devices you can add exist for vehicles without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop reading the pump.
- The moment you notice, stop: less petrol in your tank makes a weaker mixture. What to do next doesn't change, though — still do not start the vehicle.
Put petrol in a diesel in Pennywell already?
Then the order of things is short. Don't crank it, and do not turn the ignition on. Yet at the forecourt, at BP or anywhere else? Ask the attendants to help you push the car away from the pump. Next, 0333 366 0103. We will ask what went in, about how much, and if it has been run.
If it was AdBlue instead of petrol, say so. That is a separate issue — corrosion and deposits rather than lost protection — and it has its own page for Pennywell.
Pennywell petrol in a diesel jobs: why one costs more than another
Four separate tasks lie behind the four scenarios above — which is why there's no honest single quote. The situation itself does most of the work of moving the cost. Two things follow that: the petrol that went in as a share of what your tank takes, then the spot the car is in and whether a technician can get to it safely.
Before any quote, not after, we ask three queries: the fuel that got in, the amount, and if it has run. That is why. A range turns into a straight figure when the answers are in.
About Pennywell
Pennywell is a suburban area located on the riverside in Tyne and Wear, with an elevation of 69 metres above sea level. Pennywell sits approximately 2.4 miles from Sunderland city centre and is surrounded by nearby places such as South Hylton, Hastings Hill, and Grindon. Pennywell has a population of around 6449 residents and predominantly features semi-detached housing. Pennywell is situated in the North East region of England, about 240.6 miles north of London.
Fuel drain cover across Tyne and Wear, Pennywell included
South Hylton, Hastings Hill and Grindon are among the spots around Pennywell that the same teams work, answering petrol in diesel jobs across Pennywell's SR postcode area. Our engineers drain wherever the car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Pennywell: still at the petrol pump?
Then, you could not be in a better position. Switched off it stays; then call.