Petrol in a Diesel Car in Bridge End: How Worried Should You Be?
Provided it hasn't been started, worry less than you probably are. Till the ignition primes your pump, your starter turns, or the vehicle is driven, petrol in a diesel tank simply rests there and does no harm. Which makes the honest reply to the first Bridge End question — "have I ruined it?" — normally no. Leave your motor off then call Petrol in Diesel — that keeps it like that. Further down, you will find what petrol actually does inside a diesel, how far it may have gone, and how to stop it happening to you again.
The motor and petrol in a diesel: what goes on
Two jobs fall to diesel on its route round a motor. Before it combusts, it protects — and then it combusts. What keeps the surfaces inside the high-pressure pump and the injectors from wearing against one another is the diesel passing through them — they're designed to very fine clearances.
Petrol does the first task badly and the second not at all. It's runnier than diesel and strips away the lubrication the system hinges on, and so a pump running on a petrol mix is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That is where the clattering comes from.
Put these together and the shape of the issue is clear. Not contact but movement is what causes the harm. Where the petrol is only in the tank, it is an issue of fuel, nothing more. 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 your fuel to the fuel injectors downstream.
Four situations our technicians see in Bridge End: how bad is petrol in a diesel?
Fuelled up, not once started. The best case there is. The petrol is inside the tank and only that tank, and the task is a drain and a flush where the car stands. This is the one scenario that can only really take place at a forecourt, as anywhere else the vehicle has been driven to get there.
Started for a second, or just the ignition on. Once primed, the system has pulled petrol out of that tank up to the fuel filter and the lines. Drain, flush, see to the fuel filter: still usually easy.
Your pump has spent a few miles on weakened fuel — that's what driving the vehicle meant. The work is that tank, your lines, the fuel filter and clean fuel through the entire system, and how hard the vehicle was driven matters as much as how far. On the school run to Dodleston CofE Primary School, the mileage is short. Very different once more: a run to Wrexham, under 5 miles away, or some distance on the M56, under 15 miles from Bridge End, where the engine kept working hard.
Driven on until it protested — clattering, smoke, a ragged idle, a dead throttle. The engine is telling you the fuel is no longer acting like diesel. Pull up wherever you are — the verge on Hawarden Road, a lay-by, a side street — and leave the vehicle where it is. A car stopped early very seldom has permanent damage, because the fuel drain and the flush-through, which still come first, sort it out.
Petrol in a diesel stories Bridge End motorists hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing is removed when you top up — that tank simply holds more of the same blend. The assumption behind the guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
If anything, the opposite is true. Myth: "A newer diesel can cope with a bit of petrol." A newer diesel sends its fuel through finer parts at higher pressure, which makes the lubrication matter more, not less.
The myth that catches people off guard: if it starts and drives, it must be unharmed. Diesel in a petrol motor usually leaves a motor that won't run: the motorist stops, and so does the damage. 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. A running engine does not mean fine.
An outdated fix for a distinct problem is behind this one. Myth: "Add some two-stroke oil and drive it home." What petrol has thinned stays weakened, and that petrol remains inside that tank anyway.
"Drain it yourself and you are sorted" — a myth, because after it has been running some petrol sits in the filter and lines, ready to go right back through the pump on your next start. Clearing petrol into a can by the roadside is also really dangerous.
How it happens: petrol in a diesel
It's seldom carelessness, and nobody does it on purpose. The petrol nozzle is the smaller of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol motor at all. The forecourt makes it easy, and the slip runs one way.
Routine and the vehicle getting out of step is when it occurs. Courtesy car, hire car, or a motor that is new. Two cars on one drive, one petrol, one diesel. A familiar forecourt with the pumps in a different order. A rushed fill en route to Caergwrle with a train to catch. A new-to-you diesel BMW 3 Series, its first fuelling, and a motorist accustomed to petrol: precisely when it takes place. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of kids.
Bridge End people: how to avoid petrol in a diesel next time
- Green for unleaded and black for diesel is usual in the UK — yet not on each forecourt. Trust the label on the pump, not the colour.
- Check the filler flap. Many vehicles state the fuel type inside the flap or on the cap. Look at it on the first fill in any motor you do not know.
- Good intentions do less than a sticker or a fob in a vivid colour on the diesel's key when a household has one of each. So label it.
- It sounds silly and it works: on the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the pump.
- 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.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to block a petrol nozzle, and add-on devices are available for motors without one. They are a safety net, not a reason to stop reading the pump.
- Stop as soon as you realise. Less petrol inside your tank means a weaker mixture. It doesn't change what to do next, which is still not to crank it.
Already put petrol in a diesel in Bridge End?
Then the order of things is brief. Never start the car, and do not switch the ignition on. Yet on the forecourt, at Gulf or anywhere else? Ask the staff 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 has been run.
If it was AdBlue instead of petrol, say so. That's a different issue — corrosion and deposits and not lost lubrication — and it has its own page for Bridge End.
What makes one Bridge End petrol in a diesel task cost more than the next
An honest single price does not exist here: four situations, four separate tasks. The scenario itself does most of the work of moving the cost. Where the car is matters too, and whether a technician can safely get to it, after the proportion of petrol to what your tank holds.
Three queries come first, before quoting, instead of after — what was put in, how much, has it run — and that is the reason. Those answers are what turn a range into one firm number.
About Bridge End itself
Bridge End is a suburban area situated on the riverside in Flintshire, Wales, with a mix of semi-detached housing and a population of around 1915 residents. Bridge End lies close to the nearby settlements of Caergwrle, Abermorddu, and Caer Estyn, and is approximately 4.5 miles from the city of Wrexham. Bridge End occupies a relatively low-lying area, with an elevation of around 82 metres above sea level. Bridge End is also within commuting distance of major cities, being around 165 miles from London.
Across Flintshire and around Bridge End: fuel drain cover
Caergwrle, Abermorddu and Caer Estyn are among the places around Bridge End that the same teams work, answering petrol in diesel jobs across Bridge End's LL postcode area. You need not bring your car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots we drain.
Still at the pump in Bridge End?
The best position there is, then — that's where you are. Ring, and leave it turned off.