Petrol in a Diesel Car in Liss Forest: How Worried Should You Be?
Provided it has not been started, worry far less than you probably are. Everyone around Liss Forest starts with "have I ruined it?", and the fair answer is normally no: petrol left in the tank of a diesel stays harmless until priming, cranking or driving draws it into the system. Keep it like that: leave the motor off then phone Petrol in Diesel. Keep reading for three things: the effect petrol has inside a diesel engine, the clues of how far it has spread, and ways to make sure you don't do it again.
What petrol in a diesel does to your engine
Diesel does two tasks on its way through an engine. Before it ignites, it protects — and then it ignites. Very fine tolerances go into the injectors and the high-pressure fuel pump, and just the diesel flowing through stops their surfaces grinding together.
Of those two tasks, petrol handles the first badly and the second not at all. Being less viscous than diesel, petrol strips out the protection a fuel system needs, leaving a pump running on that mixture to wear itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is where you get the knocking.
Seen together, they make clear what shape the problem takes. It's circulation that does the damage, not contact. A tank with petrol in it is a fuel issue. After the pump has been working on that petrol, a mechanical problem has begun: anything shed by a pump that's grinding travels downstream to the injectors with the fuel.
How serious is petrol in a diesel? Four scenarios we see in Liss Forest
Filled up, not once started. The best case there can be. That petrol is in the tank and just that tank, and the task is a drain and a flush where your car sits. This is the one scenario that can only truly happen on a forecourt, because anywhere else your car has been driven to get there.
The ignition switched on, or a brief start. The fuel system has been bled, so petrol has left the tank and got to the fuel filter and the fuel lines. Drain, flush, deal with the filter: still normally simple.
Those few miles driven were your pump working on fuel weakened by petrol the whole way. The work is the tank, the lines, the filter and clean fuel through the entire system, and how hard your car was driven matters as much as how far. A school run to Greatham Primary School is one matter. Any mileage on the Waterlooville Bypass, under 15 miles from Liss Forest, means the motor working hard throughout, and a run to Chichester, under 25 miles away, is a very different job as well.
Driven on till it complained — knocking, smoke, a ragged idle, a soft throttle. The fuel isn't acting like diesel any more, and the motor is telling you. Stop wherever you are — the verge on Pine Walk, a lay-by, a side street — then leave the vehicle where it is. The fuel drain and flush still go first, and they deal with it: if a car is pulled over early, permanent damage is very rare.
Myths Liss Forest drivers hear about petrol in a diesel
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Topping up takes out nothing; it gives you a bigger tank of the same mixture. The idea behind that advice — that diesel fuel systems accept petrol by percentage — is wrong.
Myth: a current diesel copes with a bit of petrol. If anything, the reverse. Protection matters more on current diesels, not less, since their fuel passes through smaller parts at higher pressure.
"It starts, it drives, so no harm done" — the myth that catches most motorists than any other. The motorist of a petrol engine fed diesel normally stops, since it will not run, and the harm stops there. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile the pump wears. Running does not mean fine.
Myth: a two-stroke additive makes it safe to drive home. It was an old fix, supposed for another issue. That petrol is still in your tank afterwards, and whatever it has weakened isn't put back.
Myth: "Drain the tank yourself and you're sorted." After the motor has been run, some of that petrol is no longer in that tank: it's in the filter and your lines, and it goes right back through your pump on your next start. Besides, petrol drained into a can by the road is truly dangerous.
How does petrol in a diesel happen?
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, while the diesel one mostly will not fit a petrol motor. That's how the forecourt makes it easy.
When routine and your car stop matching, it occurs. A new motor, a hire car or a courtesy car. Households running one of each, petrol and diesel. A well-known forecourt with the pumps in a different order. Fuelling up in a rush en route to Liss, with a train to catch. A new-to-you diesel Volkswagen Passat, its first fuelling, and a motorist used to petrol: exactly when it occurs. With rain, a call coming in, or children to deal with, your hand just does what it always has.
Preventing petrol in a diesel next time you fill up in Liss Forest
- A green handle 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 your first fill in a motor you do not know.
- Good intentions count for less than a sticker or a fob in a vivid colour on your diesel's key when a house has one of each. So mark it.
- Before the nozzle leaves the petrol pump the first time you fuel a hired or new vehicle, say "diesel" out loud. Silly, perhaps, yet it does the trick.
- While you're thinking about something else, this is an easy mistake to make — so tuck the phone away.
- 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 backstop, not a reason to stop checking the pump.
- The moment you realise, stop: less petrol in your tank means a thinner blend. What to do next doesn't change, though — still do not fire it up.
Put petrol in a diesel in Liss Forest already?
Then the order of things is brief. Leave it unstarted, with the ignition switched off as well. If you're still on the forecourt — Shell or anywhere else — ask the staff to help you roll it clear of the petrol pump. Phone 0333 366 0103 next, with three facts — your fuel, the approximate amount, and if it has run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a separate issue — Liss Forest has a page just for it.
What makes one Liss Forest petrol in a diesel job cost more than the next
A fair single price doesn't exist here: four situations, four separate tasks. The scenario itself does most of the work of moving the cost. Where your car is counts too, and whether a van can safely get to it, after the ratio of petrol to what the tank takes.
Before any quote, not after, we ask three questions: the fuel that got in, its amount, and whether it has run. That is why. A range becomes a straight figure once the replies are in.
About Liss Forest and its setting
Liss Forest is a suburban area situated near the River Rother in Hampshire, with Liss Forest being a residential community at an elevation of 81 metres. Liss Forest lies within commuting distance of London, approximately 45 miles away, and is close to the city of Chichester. Liss Forest is characterised by its predominantly detached housing stock and is near other local places such as The Mint and Burgates.
Across Hampshire and in Liss Forest: fuel drain cover
Liss Forest rests in the GU postcode area, and the vans that answer petrol in diesel call-outs there work the places around it as well — The Mint, Burgates and East Liss among them. We drain where your vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
At the pump around Liss Forest, still?
Then you are in the best position there can be. Leave the car turned off, and ring.