Should You Worry? Petrol in a Diesel Car in Lower Padworth
Provided it has not been started, you can worry less than you probably are. Petrol sitting in a diesel tank does nothing to your motor until something pulls it through the fuel system — the ignition priming your pump, your starter, or the drive itself. So the honest answer to the first query everyone in Lower Padworth asks, "have I wrecked it?", is normally no. To keep the car that way, ring Petrol in Diesel then leave your motor switched off. Below, this page sets out what petrol actually 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 the engine?
On its way through a motor, diesel does two tasks. It protects to begin with, and after that does it burn. Built to extremely fine gaps, the fuel injectors and your pump depend on the diesel flowing through them to stop their surfaces wearing against one another.
The second job petrol does not do at all, and the first it does badly. A pump working on a petrol mix is wearing itself out, because petrol is thinner than diesel and takes away the lubrication the fuel system relies on. Petrol is also made to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that's where the knocking comes.
Seen together, they show the shape the trouble has. Not contact but movement is what does the harm. Any tank with petrol in it 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 moves on with the fuel to the injectors beyond it.
Four scenarios our engineers see around Lower Padworth: how bad is petrol in a diesel?
Filled up, and never started: no case is better. Being at a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With the petrol kept inside that tank alone, it's cleared and purged right where it stands, and nothing more is needed.
Ignition on, or started for a second. With your system primed, your lines and filter already hold petrol that came from that tank. Still normally simple: drain, flush, and the filter seen to.
Driven a couple of miles. Now your pump has spent those miles running on thinned fuel. Mileage is only half of it; how hard it was driven matters just as much. Either way this work includes the tank, your lines, the filter and fresh fuel through the entire circuit. Driving the kids to Beenham Primary School is one sort of trip. Very different again: a run to Oxford, under 25 miles away, or any distance on the M4, under 5 miles from Lower Padworth, where the motor kept labouring hard.
Driven till it protested. Knocking, a ragged idle, smoke, a throttle that has gone soft. What you are hearing is the engine reporting fuel that no longer acts like diesel. Whether it is the verge on Back Lane, a lay-by or a side road, stop where you are then leave it. What comes first is still the drain and flush-through, and that sorts it out, with long-term damage very unusual when a vehicle is stopped quickly.
Petrol in a diesel myths Lower Padworth people hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. A bigger tank of the same mixture is all it gives, since topping up takes out nothing. That guidance supposes a diesel fuel system tolerates petrol by percentage. It doesn't.
Not so: a current diesel copes with a bit of petrol. If anything, the opposite. A modern diesel runs its fuel through more precise parts at higher pressure, which makes the lubrication matter more, not less.
"It starts, it drives, and so no harm done" — the myth that trips up most 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. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile the pump grinds. Running doesn't mean fine.
Not so: a two-stroke additive lets you to drive home. It was an old fix, supposed for another issue. The petrol is still inside your tank after that, and what it has thinned isn't put back.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol lies in the filter and lines, ready to go right back through your pump at your next start. And, a can of petrol filled by the roadside is truly hazardous.
Why petrol in a diesel takes place at all
Carelessness is rarely the cause, and nobody means to do it. A diesel nozzle mostly won't fit a petrol motor, but the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake simple, and only in that direction.
It occurs when routine and the car stop matching. A vehicle that is new to you — hired, on loan as a courtesy car, or brand new. A household with one petrol and one diesel on the drive. Your usual forecourt, its pumps now in a different order. A train to catch, and a hurried fill on the way to Aldermaston. Years of petrol motors behind you, a diesel Renault Megane in front of you at the forecourt for its first tank — that's when. The hand repeats what it has always done when you add rain, a phone call or a back seat full of children.
Next time you fill up around Lower Padworth: preventing petrol in a diesel
- The label is what matters, and so check the petrol pump rather than the colour: in the UK unleaded handles are normally green and diesel black, but not on every forecourt.
- The first fill in a strange car is the time to check the filler flap — inside it, or on the cap, plenty of motors state the fuel they take.
- Good intentions do less than a sticker or a fob in a vivid colour on your diesel's key when a home has one of each. So mark it.
- Before the nozzle leaves the pump the first time you fuel a hired or new car, say "diesel" out loud. Silly, perhaps, but it does the trick.
- Put the phone away. This is an easy mistake to make while you are thinking about something else.
- Some diesels come with a filler designed to block 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 reading the pump.
- Stop as soon as you realise. Less petrol inside the tank makes a weaker mixture. It doesn't change what to do next, which is still not to fire it up.
Petrol already in a diesel around Lower Padworth? Begin here
The order of things is short, then. Leave it unstarted, with the ignition switched off too. Ask the attendants to help you roll it clear of the pump if you're still on the forecourt, whether that's Shell or anywhere else. Call 0333 366 0103 next, with three facts — the fuel, the approximate quantity, and if it has run.
If it was AdBlue instead of petrol, say so. That is a different problem — corrosion and deposits rather than lost protection — and it has its own page for Lower Padworth.
One petrol in a diesel job in Lower Padworth costs more than another. Why?
The four situations above are four different jobs, so no single quote for this would be fair. Mostly, your cost shifts with which one you are in. The share matters next, meaning how much of that tank is petrol, and then the location of the car and whether reaching it is safe for a technician.
That's why our engineers ask three questions before quoting instead of after: what got in, how much, and if it has run. A range becomes a straight figure once those replies are in.
About Lower Padworth itself
Lower Padworth is a small village in Berkshire, situated on the banks of the River Kennet at an elevation of around 53 metres. Lower Padworth has a mix of housing types, but semi-detached homes are particularly prevalent, and its location near the wharf at Aldermaston makes it a notable point on the local riverside. Lower Padworth is within commuting distance of major cities, including Oxford, which is approximately 24 miles away.
Lower Padworth and Berkshire: where our fuel drain cover reaches
Petrol in diesel calls around Lower Padworth — part of the RG postcode area — go to teams that likewise cover the places around it, Aldermaston Wharf, Beenham Stocks and Ufton Green among them. A forecourt, a supermarket car park, a lay-by or your own drive are all places our technicians work, and your car doesn't need to come to us.
At the petrol pump in Lower Padworth, right now?
The best position there is, then — that's where you are. Keep it off. Phone.