Westfield: Petrol in a Diesel Car? How Worried to Be
Far less than you likely are, if it hasn't been started. "Have I ruined it?" is the first question anyone in Westfield asks, and the honest answer is generally no, since petrol resting in a diesel tank hurts nothing until it's drawn through the system — by ignition priming, by the starter, or by being driven. Leave your motor off then phone Petrol in Diesel — that is how you keep it like that. What petrol really does to a diesel, how to gauge how far it has gone, and how to keep it from happening a second time: that is the rest of this page.
The motor and petrol in a diesel: what happens
Passing through an engine, diesel is doing two jobs at once. Before it combusts, it lubricates — and then it burns. What keeps the surfaces inside the high-pressure pump and the fuel injectors from grinding against one another is your diesel passing through them — they're designed to very fine tolerances.
The second job petrol doesn't do at all, and the first it does poorly. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump on that mixture to wear itself. It's equally made to resist igniting under compression — the opposite of what a diesel needs — which is why you get the knocking.
Put those together and the shape of the issue is plain. It is circulation that causes the damage, not contact. Any tank with petrol in it is a fuel problem. The beginning 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 your injectors downstream.
How bad is petrol in a diesel? Four scenarios our technicians see in Westfield
Filled up, never started. The best case there can be. That petrol is in that tank and only that tank, and the task is a drain and a flush where the car stands. This is the one scenario that can only really occur on a forecourt, since anywhere else the car has been driven to get there.
Ignition on, or started for a second. The system has been primed, and so petrol has left that tank and reached the fuel filter and your lines. Still normally easy: drain, flush, and your filter dealt with.
The pump has spent a few miles on thinned fuel — that is what driving the vehicle meant. The work is that tank, the 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 Cradley CofE Primary School is one thing. Any distance on the M5, under 10 miles from Westfield, means the engine has worked hard throughout, and a run to Worcester, under 10 miles away, makes a very different task as well.
Driven on till it complained — clattering, smoke, an uneven idle, a soft throttle. That is the engine telling you its fuel has stopped acting like diesel. Leave it wherever it has stopped: a lay-by, a quiet street, the verge on B4220. Lasting damage is very unusual if a vehicle is stopped soon, and the drain and flush-through that still come first take care of it.
Petrol in a diesel myths Westfield motorists hear
"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 are left with a bigger tank, still the same mixture. The assumption behind that advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: a newer diesel copes with a bit of petrol. Rather, the reverse. Protection counts more on newer diesels, not less, because their fuel runs through smaller parts at higher pressure.
This is the one that fools people. Myth: "If it starts and drives, there is no damage done." Any petrol motor fed diesel normally won't run, so the driver stops 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 will; meanwhile the pump grinds. Fine and running aren't the same at all.
Myth: "Add some two-stroke oil and drive it home." It's an old workaround for a different issue. That petrol is still inside your tank after that, and what it has weakened is not put back.
Once the engine has been run, part of that petrol is in your filter and your lines, not your tank — and the next start pulls it straight back through the pump. So the myth "drain that tank yourself and you are sorted" does not stand up. On top of that, petrol drained into a can by the road is genuinely hazardous.
Why petrol in a diesel occurs at all
It is seldom carelessness, and no one does it on purpose. A diesel nozzle generally will not fit a petrol vehicle, yet the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake simple, and just in one direction.
The moment routine stops matching the vehicle is the moment it takes place. Any vehicle that's new to you — a hire car, on loan as a courtesy car, or just bought. A household with one petrol and one diesel on the driveway. Your normal forecourt, its pumps now in a different order. Rushing for a train at Colwall and fuelling up en route. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that is when. Throw in a back seat full of kids, a phone call or rain, and habit takes over.
Next time you fill up around Westfield: avoiding petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Check the pump's label; the colour is only a clue.
- Plenty of vehicles state the fuel type inside your filler flap or on the cap, and so check there on the first fill in a motor you do not know.
- Mark your key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- It seems daft and it works: on your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump.
- While you are thinking about something else, this is an easy mistake to make — so put the phone away.
- Some diesels come with a filler built to reject a petrol nozzle, and devices you can add exist for cars without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop reading the pump.
- Spotting it mid-fill? Stop there and then. A weaker mixture results from less petrol in the tank, yet the next step stays the same: don't crank it.
Already put petrol in a diesel around Westfield?
The order of things is short, then. Starting it is out, and so is turning on the ignition. If you are still on the forecourt — Texaco or anywhere else — ask the staff to help you roll it away from the petrol pump. Then phone 0333 366 0103 and tell us what got in, roughly how much, and if it's run.
Corrosion and deposits are the trouble with AdBlue, whereas petrol brings lost protection. So if it was AdBlue, say so — and read its own Westfield page.
One petrol in a diesel task around Westfield costs more than another. Why?
There is no fair single price for this, because the four situations above are four different jobs. The situation itself does most of the work of moving your cost. Where the vehicle is matters too, and whether our van can safely get to it, after the ratio of petrol to what the tank takes.
What was put in, how much, and if it's run — three queries our technicians ask before pricing, not after, for exactly that reason. Those answers are what turn a range into one firm number.
About Westfield
Westfield is a village in Herefordshire, situated on the banks of a river at an elevation of around 94 metres. Westfield lies approximately 9 miles from Worcester and 106 miles from London, with nearby villages including Stony Cross, Cradley, and Mathon. Westfield has a population of around 775 people, predominantly living in detached houses. Westfield is characterized by its rural setting and residential community.
Westfield and Herefordshire: where our fuel drain cover reaches
Westfield sits in the WR postcode area, and the vans that answer petrol in diesel calls there work the places around it as well — Stony Cross, Cradley and Mathon among them. You need not bring your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots where we work.
At the petrol pump around Westfield, still?
Then you are in the best place there can be. Ring, and keep it switched off.