Petrol in a Diesel Car in Shaw: How Worried Should You Be?
Far less than you likely are, if it has not been started. Petrol sitting in a diesel tank does nothing to your motor until something draws it through the fuel system — your ignition priming your pump, your starter, or driving itself. So the fair answer to the first query anyone in Shaw asks, "have I ruined it?", is usually no. Keep it like that: leave your motor off then phone Petrol in Diesel. Further down, you will find what petrol really does inside a diesel, how far it may have gone, and how to stop it happening to you again.
The motor and petrol in a diesel: what goes on
Diesel does two tasks on its way through a motor. Before it combusts, it lubricates — and then it burns. Your high-pressure pump and the fuel injectors are designed to extremely fine gaps, and the diesel passing through them is what stops those surfaces from wearing down against one another.
Of these two tasks, petrol handles the first badly and the second never. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, so a pump on that mixture wearing itself. It's also made to resist igniting under compression — the opposite of what a diesel needs — which is where you get the clattering.
Put those together and the shape of the trouble is plain. The damage is done by circulation, not by contact. Petrol in the tank is a fuel issue. Once the pump has been labouring on that petrol, a mechanical fault has started: anything shed by a pump that's wearing down travels onward to your injectors with the fuel.
Petrol in a diesel in Shaw: how bad is it? Four situations
The best case there can be: filled up, not once started. On a forecourt, and really only there, that petrol is still limited to that tank — since anywhere else the vehicle was driven to get to it. The job is draining and flushing on the spot.
Your ignition switched on, or a brief start. With your system primed, the fuel lines and filter already hold petrol that has come from the tank. That is normally still a straightforward job — a drain, a flush, and your filter seen to.
Driven a few miles. Now your pump has spent these miles working on diluted fuel. The work is that tank, the fuel lines, the filter and clean fuel through the whole system, and how hard the car was driven counts as much as how far. A school run to The Winchcombe School is one thing. Any distance on the M4, under 3 miles from Shaw, means the motor working hard throughout, and a run to Oxford, under 25 miles away, is a very different task too.
Driven until it protested. Rattling, an uneven idle, smoke, a throttle that has gone soft. What you are hearing is your motor reporting fuel that no longer behaves like diesel. Whether it is the verge on Love Lane, a lay-by or a side road, stop where you are then leave it. What goes first is still the drain and flush, and that takes care of it, with long-term damage very uncommon when a car is stopped early.
Petrol in a diesel stories Shaw drivers hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. A bigger tank of the same mix is all you get, because topping up takes out nothing. That guidance assumes a diesel fuel system tolerates petrol by percentage. It does not.
If anything, the opposite holds. Myth: "A current diesel can cope with a bit of petrol." Smaller parts and higher pressure are the way a newer diesel runs its fuel, and that makes the lubrication count more, not less.
One myth that catches people off guard: if it starts and drives, it must be unharmed. Any petrol motor fed diesel generally won't run, so the driver stops and the harm stops with them. While the pump grinds, a diesel fed petrol normally starts, idles and drives away as if nothing has happened. Running isn't the same as fine.
Myth: a two-stroke additive makes it safe to drive home. It is an old fix, supposed for another fault. What petrol has diluted stays weakened, and that petrol stays inside your tank anyway.
"Drain it yourself and you're sorted" — a myth, because after it's been running some petrol lies in the fuel filter and lines, ready to go straight back through your pump on your next start. Draining petrol into a can at the roadside is also genuinely risky.
Petrol in a diesel: how does it occur?
It's seldom carelessness, and nobody does it on purpose. A diesel nozzle generally won't go into a petrol car, but the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error easy, and just in one direction.
When habit and the vehicle stop matching, it takes place. Courtesy car, hire car, or a motor that's brand new. A household with one petrol and one diesel on the driveway. Your normal forecourt, its pumps suddenly in a different order. A train to catch, and a hurried fill en route to Newbury. Precisely the moment it happens: after years of driving petrol, someone fills a diesel Volkswagen Golf for the first time. With rain, a call coming in, or children to deal with, the hand simply does what it always has.
How to prevent petrol in a diesel on your next fill-up in Shaw
- A green handle for unleaded and black for diesel is usual in the UK — but not on every forecourt. Go by the label on the petrol pump, not the colour.
- The first fill in a new vehicle is the time to check your filler flap — on it, or on the cap, plenty of cars state which fuel to use.
- One of each in the household? Label the key to your diesel — a bright fob, a sticker — because meaning to remember is not enough.
- Before the nozzle comes off the petrol pump the first time you fuel a hired or new vehicle, say "diesel" aloud. Silly, perhaps, but it does the trick.
- Mistakes like this are easy to make while your mind is on something else, so your phone goes away.
- Some diesels have a filler designed to reject a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- The moment you realise, stop: less petrol in the tank means a thinner blend. What to do next does not change, though — still do not fire it up.
Petrol already in a diesel around Shaw? Start here
Then, there's just a short order of things. Don't switch the ignition on, and don't start it. If you're still on the forecourt — BP or anywhere else — ask the staff to help you push the car away from the petrol pump. Call 0333 366 0103 next, with three facts — the fuel, the rough quantity, and whether it's run.
If it was AdBlue instead of petrol, say so. That is a separate fault — corrosion and deposits and not lost lubrication — and it has its own page for Shaw.
One petrol in a diesel job around Shaw costs more than another. Why?
There's no fair single price for this, since the four scenarios above are four different jobs. What shifts the cost is chiefly which of them you're in. Two things follow that: the petrol that was put in as a proportion of what your tank holds, then the spot your car is in and whether a van can get to it safely.
That is why our technicians ask three queries before quoting instead of after: what got in, how much, and whether it has run. A range becomes a straight figure when those answers are in.
About Shaw itself
Shaw is a suburban area in Berkshire, situated near the lakeside and surrounded by nearby places such as Donnington and Speenhamland. Shaw sits at an elevation of 82 metres, within commuting distance of Oxford, which is approximately 23.5 miles away. Shaw has a population of around 2316 people, predominantly living in semi-detached housing. Shaw is also within reach of London, being around 51.6 miles from the capital city.
Fuel drain cover in Shaw and across Berkshire
Shaw rests in the RG postcode area, and our teams that answer petrol in diesel jobs there work the spots near it as well — Donnington, Speenhamland and Newbury among them. Our technicians drain where the car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
Shaw: still at the pump?
Then you're in the best position there can be. Switched off it remains; then call.