Petrol in a Diesel Car in St Johns: How Worried Should You Be?
Likely less than you are now — provided nobody has started the vehicle. Petrol sitting in a diesel tank does nothing to your engine till something draws it through the fuel system — your ignition priming your pump, your starter, or the drive itself. So the honest answer to the first query everyone around St Johns asks, "have I ruined it?", is normally no. Petrol in Diesel is who to ring, with the engine kept off, so it remains that way. The remainder 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 does not happen to you a second time.
What petrol in a diesel does to the motor
Two jobs fall to diesel on its journey through a motor. It burns, and before it burns it lubricates. Very fine gaps are built into your injectors and the high-pressure fuel pump, and just your diesel flowing through keeps those surfaces from grinding together.
The second task petrol doesn't do at all, and the first it does poorly. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, so a pump on the mixture to wear itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is why you get the clattering.
Put these together and the shape of the problem is plain. It is circulation that causes the damage, not contact. All a tank with petrol in it amounts to is a fuel issue. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to your injectors further on.
Petrol in a diesel around St Johns: how bad is it? Four situations
Fuelled, and not started: nothing beats it. On a forecourt, and really only there, the petrol is still confined to your tank — since anywhere else the vehicle was driven to reach it. The task is draining and purging on the spot.
Ignition on, or started for a second. The system has been bled, and so petrol has left that tank and reached the filter and your lines. Drain, flush, see to the fuel filter: still usually easy.
Your pump now worked a few miles on thinned fuel — that's what driving the car does. Mileage is only half of that; how hard it was driven matters just as much. Either way the work runs to that tank, your lines, the fuel filter and fresh fuel through the whole circuit. The school run to St Stephen's CofE Primary School is one matter. Very different a second time: a run to London, under 5 miles away, or any miles on the M11, under 10 miles from St Johns, where your engine kept labouring hard.
Clattering, a lumpy idle, smoke, a throttle gone soft: driven till it complained. The fuel isn't behaving like diesel any more, and your engine is saying so. Stop where you are — on the verge on Lind Street, at the kerb, down a side road — and do not move it. What comes first is still the drain and flush-through, and that deals with it, with long-term damage very rare when a vehicle is stopped soon.
Stories St Johns motorists hear about petrol in a diesel
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing is removed by topping up — you're left with a bigger tank, still the same mix. That advice presumes a diesel fuel system tolerates petrol by percentage. It doesn't.
"Current diesels can handle a little petrol" — a myth, and closer to 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.
"It starts, it drives, so there is no harm" — the myth that catches more people than any other. The driver of a petrol engine fed diesel usually stops, because it will not run, and the harm stops with them. While your pump wears, a diesel fed petrol normally starts, idles 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 is an outdated fix for a distinct fault. It doesn't put back what petrol has thinned, and the petrol is still inside that tank later.
The next start sends petrol back round the pump out of your lines and the fuel filter, where some of that ends up once your engine has been run. That is why draining the tank yourself doesn't sort it — a myth. Emptying petrol into a can at the kerbside is also really hazardous.
Why petrol in a diesel takes place so easily
On purpose? Never. Through carelessness? Rarely, if ever. A diesel nozzle mostly won't go into a petrol vehicle, but the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error straightforward, and only in one direction.
The moment routine stops matching the car is the moment it occurs. Any motor that is new to you — a hire car, on loan as a courtesy car, or brand new. Households running one of each, petrol and diesel. Your normal forecourt, its pumps suddenly in a different order. A hurried fill on the way to the nearest station with a train to catch. The first fill-up in a diesel Renault Clio after years of driving petrol is exactly the moment it occurs. Throw in rain, a phone call or a back seat full of children, and the hand repeats what it has always done.
Avoiding petrol in a diesel next time you fill up in St Johns
- A green handle for unleaded and black for diesel is normal in the UK — but not on every forecourt. Trust the label on the pump, not the colour.
- Many motors state the fuel inside the filler flap or on the cap, so check there on the first fill in any vehicle you do not know.
- Good intentions count for less than a sticker or a fob in a bright colour on the diesel's key when a household has one of each. So label it.
- Before the nozzle leaves the pump the first time you fuel a hired or new car, say "diesel" out loud. Silly, yes, but it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, so put the phone away then keep your mind on the petrol pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to refuse a petrol nozzle, and add-on devices exist for cars without one. They are a safety net, not a reason to stop reading the pump.
- Stop the moment you notice. Less petrol in that tank means a thinner mixture. It doesn't change what to do next, which is still not to crank it.
St Johns: already put petrol in a diesel?
Then the order of things is short. Starting it is out, and so is switching on the ignition. The attendants on the forecourt — whether at Esso itself or wherever you filled up — will usually help roll it clear of the pump if you ask. Ring 0333 366 0103 next, with three facts — the fuel, the rough amount, and whether it has run.
Corrosion and deposits are the problem with AdBlue, where petrol brings lost lubrication. So if it was AdBlue, say so — and see its own St Johns page.
One petrol in a diesel job in St Johns costs more than another. Why?
Four different tasks lie behind the four situations above — which is why there's no fair single quote. Chiefly, your cost shifts with which one you are in. The proportion counts next, meaning how much of the tank is petrol, followed by the location of your car and whether getting to it is safe for our van.
Ahead of any quote, not after, we ask three queries: your fuel that was put in, the quantity, and whether it has run. That's why. The replies change a range into a straight figure.
About St Johns itself
St Johns is a suburban area in south-east London, situated on the banks of the River Thames. St Johns is characterized by its predominantly flat-based housing and its proximity to central London, being approximately 5 miles from the city centre. St Johns is close to other notable areas such as Deptford, Greenwich, and New Cross, and its riverside location offers scenic views of the Thames. St Johns has a relatively low elevation of around 8 metres above sea level.
Fuel drain cover across Greater London, St Johns included
Deptford, Greenwich and New Cross are among the places near St Johns that the same teams work, answering petrol in diesel calls across St Johns's SE postcode area. The car doesn't need to come to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Still at the pump around St Johns?
Nothing beats it: that is where you now are. Turned off it stays; then ring.