Petrol in a Diesel Car in Oxted: How Worried Should You Be?
Not started? Then less worried than you probably are. Until the ignition primes the pump, your starter turns, or your car is driven, petrol in a diesel tank simply rests there and does nothing. Which makes the honest reply to the first Oxted question — "have I ruined it?" — usually no. To keep the car like that, call Petrol in Diesel and leave the engine alone. The rest of this page sets out what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you a second time.
Inside your engine: what petrol in a diesel does
Passing through an engine, diesel is doing two things at the same time. Oiling comes before burning; it does both. Built to extremely fine clearances, the injectors and your pump depend on your diesel flowing through them to keep their surfaces from wearing against one another.
The second job petrol does not do at all, and the first it does badly. The knocking comes from petrol being made not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips out the protection your system depends on, and any pump running on such a blend is wearing itself.
Seen together, they show what shape the issue takes. Not contact but circulation is what does the damage. All a tank with petrol in it amounts to is a fuel fault. The start of a mechanical one is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with your fuel to the fuel injectors downstream.
Petrol in a diesel around Oxted: how bad is it? Four situations
Filled up, never started. The best case there can be. At a forecourt, and really only there, that petrol is still confined to that tank — since everywhere else the car was driven to get to it. The task is emptying and rinsing on the spot.
Your ignition switched on, or a brief start. With your system primed, your lines and filter already contain petrol that came from the tank. Drain, flush, deal with the fuel filter: still normally easy.
Driven a few miles. Now your pump has spent those miles working on diluted fuel. How hard your car was driven matters as much as how far, and the work covers that tank, your lines, the fuel filter and fresh fuel through the whole system. Driving the children to St Mary's CofE Primary School is one kind of trip. Any mileage on the M25, under a mile from Oxted, means the engine has worked hard throughout, and a run to Westminster, under 25 miles away, is a very different task as well.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone ragged. What you are hearing is your motor signalling fuel that no longer acts like diesel. Leave it wherever it stops: a lay-by, a quiet street, the verge on Amy Road. A car stopped soon very seldom has lasting damage, as the drain and the flush-through, which still go first, deal with it.
Stories Oxted motorists hear about petrol in a diesel
Myth: topping up to full with diesel makes it fine. It does not. A bigger tank of the same mix is all it gives, because topping up takes out nothing. Percentage isn't how a diesel fuel system tolerates petrol, whatever that guidance presumes.
Myth: a current diesel copes with a bit of petrol. If anything, the reverse. A current diesel runs its fuel through finer components at higher pressure, which makes the protection matter more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that fools motorists. Any petrol engine fed diesel generally won't run, so the driver stops and the damage stops with them. A diesel fed petrol generally starts, ticks over and drives away as if nothing has happened, whilst your pump grinds. Being able to run isn't proof of being fine.
An old fix for a distinct problem is behind this one. Myth: "Add some two-stroke oil and drive it home." What petrol has thinned remains weakened, and the petrol remains inside your tank anyway.
Myth: "Drain that tank yourself and you're sorted." Once the motor has run, some of that petrol is no longer inside the tank: it is in your filter and the fuel lines, and it goes straight back through the pump at your next start. And, a can of petrol filled by the kerbside is genuinely hazardous.
Petrol in a diesel: how does it occur?
On purpose? Never. Through carelessness? Seldom, if ever. One way only, because of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, whereas the diesel one generally will not fit a petrol car. That is how the forecourt makes it simple.
When routine and the vehicle stop matching, it occurs. Courtesy car, hire car, or a car that is brand new. Households running one of each, petrol and diesel. A familiar forecourt with the pumps in a different order. Fuelling up in a hurry en route to the nearest station, with a train to catch. A new-to-you diesel Renault Megane, its first fuelling, and a driver used to petrol: exactly when it takes place. The hand does what it has always done once you add rain, a phone call or a back seat full of kids.
Next time you fill up around Oxted: preventing petrol in a diesel
- 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.
- In a vehicle you do not know, look inside the flap over the filler or at the cap before your first fill: plenty of vehicles print the fuel type there.
- Good intentions do less than a sticker or a fob in a vivid colour on your diesel's key when a household has one of each. So mark it.
- Before the nozzle comes off the petrol pump the first time you fuel a hired or new vehicle, say "diesel" out loud. Daft, yes, yet it works.
- Whilst you're thinking about something else, this is an easy mistake to make — so put the phone away.
- Some diesels have a filler designed to reject a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump.
- Less petrol means a weaker blend, and so stop as soon as you notice — while remembering that the next step is unchanged. It is still not to start it.
Oxted: already put petrol in a diesel?
In that case, there is just a short order of things. Do not switch the ignition on, and don't fire it up. Ask the attendants to help you roll it clear of the petrol pump if you are still on the forecourt, whether that is Shell or somewhere else. Then phone 0333 366 0103 and tell us what was put in, about how much, and whether it's run.
If it was AdBlue instead of petrol, say so. That's a different fault — corrosion and deposits rather than lost protection — and it has its own page for Oxted.
What makes one Oxted petrol in a diesel task cost more than the next
Four separate tasks lie behind the four situations above — which is why there's no fair single quote. The situation itself does most of the work of moving the cost. The proportion counts next, meaning how much of the tank is petrol, and then the position of the vehicle and whether getting to it is safe for our van.
Before any quote, not after, come three queries: the fuel that went in, the volume, and if it has run. That's why. A range turns into a straight figure once those answers are in.
About Oxted and its setting
Oxted is a town situated in the county of Surrey, England, with a riverside setting and an elevation of around 105 metres. Oxted lies approximately 18 miles south of London and is close to nearby places such as Limpsfield, Broadham Green, and Hurst Green. Oxted has a population of around 8536 people and is characterised by predominantly detached housing. Oxted benefits from its location in the South East region, with good transport links to nearby cities.
Across Surrey and around Oxted: fuel drain cover
Limpsfield, Broadham Green and Hurst Green are among the spots around Oxted that the same teams work, answering petrol in diesel jobs across Oxted's RH postcode area. A forecourt, a supermarket car park, a lay-by or your own drive are all places our technicians drain, and the car does not need to come to us.
Oxted: still at the petrol pump?
The best spot there is, then — that is where you are. Keep the car turned off, then ring.