Lipson: Petrol in a Diesel Car? How Worried to Be
Not started? Then less worried than you likely are. Petrol sitting in a diesel tank does nothing to your engine till something draws it through the fuel system — the ignition priming your pump, the starter, or the drive itself. So the honest answer to the first query everyone in Lipson asks, "have I wrecked it?", is normally no. Petrol in Diesel is who to phone, with the engine kept off, and so it remains that way. Further down, this page sets out what petrol really does inside a diesel, how far it may have gone, and how to stop it happening to you a second time.
Petrol in a diesel: what does it do to your engine?
Diesel does two tasks on its way through a motor. Lubricating comes before burning; it does both. Made to extremely fine tolerances, the fuel injectors and the pump depend on the diesel flowing through them to keep their surfaces from wearing against one another.
Badly at the first, not at all at the second: that's petrol. The knocking comes from petrol being designed not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips out the lubrication the system hinges on, and any pump working on that blend is wearing itself.
The shape of the problem is clear once you put those together. Contact does not do the damage — circulation does. All a tank with petrol in it amounts to is a fuel issue. Once your pump has been working on that petrol, a mechanical issue has started: anything shed by a pump that's wearing is carried downstream to your injectors with your fuel.
Petrol in a diesel around Lipson: how bad is it? Four situations
Fuelled, and never started: no case is better. That petrol is inside that tank and only that tank, and the job is a drain and a flush where the car sits. This is the one situation that can only truly occur on a forecourt, because anywhere else your car has been driven to get there.
Ignition on, or started for a moment. Once primed, the system has pulled petrol out of that tank up to the fuel filter and your lines. Drain, flush, deal with your filter: still normally easy.
Those few miles driven meant your pump working on fuel diluted by petrol throughout. Tank, lines, filter, then clean fuel put through the entire system: that's the work, and the way the vehicle was driven matters as much as the distance. Driving the kids to Lipson Vale Primary School is one sort of trip. Very different again: a run to Plymouth, under 3 miles away, or some miles on the M5, under 50 miles from Lipson, where the engine never stopped labouring hard.
Clattering, an uneven idle, smoke, a throttle gone soft: driven till it complained. The fuel is not behaving like diesel any more, and the motor is saying so. Pull up wherever you are — the verge on Salcombe Road, a lay-by, a side street — and leave the vehicle where it is. A vehicle pulled over early very seldom has permanent damage, as the drain and the flush-through, which still go first, take care of it.
Myths Lipson people hear about petrol in a diesel
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Nothing is removed when you top up — that tank simply carries more of the same blend. The assumption behind that advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: a current diesel copes with a bit of petrol. Rather, the reverse. More precise components and higher pressure are how a newer diesel runs its fuel, and that makes the lubrication matter more, not less.
One myth that catches people out: if it starts and drives, it must be unharmed. The motorist of a petrol motor fed diesel normally has no choice but to stop, since it will not run, and the harm stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually will; meanwhile your pump grinds. Being able to run is not the same as being fine.
An outdated fix for a distinct problem is behind this one. Myth: "Add some two-stroke oil and drive the car home." None of what petrol diluted is put back by it — and later, your tank still holds the petrol.
"Drain it yourself and you're sorted" — a myth, since after it has been running some petrol sits in the filter and lines, waiting to go right back through your pump at the next start. Draining petrol into a can by the kerbside is also genuinely risky.
How petrol ends up: petrol in a diesel
A careless moment is seldom the cause, and no one means to do it. A diesel nozzle mostly won't fit a petrol vehicle, yet the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error straightforward, and only in that direction.
Habit and your car falling out of step is how it happens. Hire cars, courtesy cars, and motors that are new to you. A household with one petrol and one diesel on the driveway. The pumps in a different order on a well-known forecourt. A rushed fill en route to Plymouth with a train to catch. Years of petrol motors behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that's when. The hand does what it has always done once you add rain, a phone call or a back seat full of children.
Avoiding petrol in a diesel next time you fill up around Lipson
- Check the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on every forecourt. The label is what matters.
- The first fill in an unfamiliar motor is the time to check the filler flap — on it, or on the cap, plenty of motors state the fuel to use.
- Label the key. In a house with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- It seems daft and it does the trick: on your first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the petrol pump.
- Put your phone away. This is an easy mistake to make while you're thinking about something else.
- 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 backstop, not a reason to stop reading the pump.
- Less petrol makes a thinner mixture, so stop the moment you notice — while remembering that the next stage is unchanged. It is still not to start the vehicle.
Already put petrol in a diesel in Lipson?
Then the order of things is short. Don't crank it, and don't turn the ignition on. The attendants on the forecourt — whether at Asda itself or wherever you filled up — will normally help push it away from the petrol pump if you ask. Call 0333 366 0103 next, with three answers — your fuel, the rough quantity, and if it's run.
Say so if it was AdBlue instead of petrol: it's a different issue, with its own page for Lipson, because AdBlue brings corrosion and deposits instead of lost lubrication.
What makes one Lipson petrol in a diesel job cost more than the next
The four situations above are four different jobs, so no single quote for this would be fair. The scenario itself does most of the work of moving the cost. Two things come after that: the petrol that got in as a proportion of what the tank takes, then the spot the vehicle is in and whether a technician can reach it safely.
What went in, how much, and if it's run — three queries our engineers ask before pricing, not after, for precisely that reason. Their replies are what change a range into one firm number.
About Lipson itself
Lipson is a suburban area located on the coast of Devon, sitting approximately 58 metres above sea level and just over a mile from Plymouth city centre. Lipson is characterized by its predominantly terraced housing stock and is situated near other local areas such as Lipson Vale and Mount Gould. Lipson is part of the larger Plymouth urban area, with nearby neighbourhoods including St Judes. Lipson has a population of around 14644 residents.
Fuel drain cover around Lipson and across Devon
Our teams answering petrol in diesel jobs around Lipson, in the PL postcode area, equally work the places near it, Lipson Vale, Mount Gould and St Judes included. The car doesn't need to move to us: we drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
In Lipson and still at the pump?
In that case, you couldn't be in a better spot. Keep it turned off, and ring.