How Worried Should You Be? Petrol in a Diesel Car in Credenhill
Likely less than you are now — provided no one has started the vehicle. Till your ignition primes the pump, the starter cranks, or your car is driven, petrol in a diesel tank just sits there and does nothing. Which makes the truthful reply to the first Credenhill question — "have I ruined it?" — usually no. Petrol in Diesel is who to phone, with your engine kept off, and so it stays that way. The rest of this page covers what petrol really does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you a second time.
Petrol in a diesel: what does it do to the engine?
Diesel does two jobs on its way through a motor. Before it burns, it protects — and then it burns. Your high-pressure pump and your injectors are made to very fine gaps, and your diesel passing through them is what stops those surfaces from wearing down against each other.
Of these two jobs, petrol handles the first badly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, so a pump running 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 hear the rattling.
Together, those leave the shape of the trouble clear. Not contact but movement is what does the damage. Where that petrol is only in your tank, it is an issue of fuel, nothing more. A pump that has been labouring on that petrol is the start of a mechanical one, and whatever a worn pump sheds moves on with the fuel to the injectors downstream.
How serious is petrol in a diesel? Four scenarios our engineers see around Credenhill
Filled up, and not started: nothing beats it. On a forecourt, and really only there, the petrol is still confined to your tank — because anywhere else the car was driven to get to it. The task is draining and cleaning on the spot.
Ignition on, or started for a moment. Your system has been bled, and so petrol has left the tank and got to the filter and the lines. Drain, flush, deal with your filter: still usually simple.
A couple of miles driven, and the pump has spent every one of them working on thinned fuel. Tank, lines, filter, then fresh fuel run through the whole circuit: that's the work, and the way your car was driven counts as much as the distance. Driving the kids to St Mary's CofE Primary School is one sort of trip. Any miles on the M50, under 15 miles from Credenhill, means the engine has worked hard throughout, and a run to Hereford, under 5 miles away, makes a very different job too.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. What you are hearing is your engine reporting fuel that no longer behaves like diesel. Leave it where it stops: a lay-by, a side street, the verge on Heritage Drive. A car pulled over early very seldom has lasting damage, because the fuel drain and the flush-through, which still come first, sort it out.
Credenhill motorists and the petrol in a diesel myths they hear
False: topping up to full with diesel makes it fine. It does not. Nothing is removed by topping up — you're left with a fuller tank, still the same mixture. The assumption behind that guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
If anything, the opposite holds. Myth: "A modern diesel can cope with a bit of petrol." A modern diesel sends its fuel through finer parts at higher pressure, which makes the protection matter more, not less.
One myth that catches drivers out: if it starts and drives, it must be unharmed. Diesel in a petrol motor normally means a motor that will not run: the motorist stops, and so does the damage. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile the pump grinds. Running doesn't mean fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It is an outdated workaround for a different issue. It doesn't put back what petrol has diluted, and the petrol is still in the tank afterwards.
Myth: "Drain the tank yourself and you're sorted." Once the engine has been run, some of the petrol is no longer in the tank: it is in the fuel filter and your lines, and it goes right back through the pump at your next start. Emptying petrol into a can at the roadside is also genuinely dangerous.
Why petrol in a diesel takes place at all
Carelessness is seldom the cause, and nobody means to do it. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol motor at all. The forecourt makes it simple, and the error runs one way.
Habit and the car falling out of step is how it occurs. Any motor that is new to you — a hire car, on loan as a courtesy car, or brand new. One petrol and one diesel on the drive of the same household. The pumps in a different order on a well-known forecourt. A train to catch, and a hurried fill on the way to Hereford. Years of petrol motors behind you, a diesel Renault Clio in front of you on the forecourt for its first tank — that is when. The hand does what it has always done once you add rain, a phone call or a back seat full of kids.
How to prevent petrol in a diesel on your next fill-up in Credenhill
- Check the pump, not the colour. In the UK unleaded handles are generally green and diesel black, yet not on each forecourt. The label is what matters.
- Many motors state the fuel inside the filler flap or on the cap, and so check there on the first fill in a car you don't know.
- Mark the 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 intending to remember.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump. It sounds silly and it works.
- Whilst you are thinking about something else, this is an easy mistake to make — so tuck your phone away.
- Add-on devices exist for cars without one, and some diesels come with a filler that won't take a petrol nozzle. Helpful — but a backstop at best, never a reason to stop checking the label.
- Spotting it halfway? Stop at once. A thinner mixture results from less petrol inside the tank, yet your next step remains the same: do not fire it up.
Credenhill: already put petrol in a diesel?
The order of things is short, then. Leave it unstarted, with the ignition off as well. Yet at the forecourt, at Asda Express or anywhere else? Ask the attendants to help you push the car clear of the pump. Phone 0333 366 0103 next, with three answers — your fuel, the approximate amount, and whether it has run.
If it was AdBlue rather than petrol, say so. That is a separate fault — corrosion and deposits rather than lost lubrication — and it has its own page for Credenhill.
One petrol in a diesel job in Credenhill costs more than another. Why?
There is no fair single quote for this, because the four scenarios above are four different tasks. The situation itself does most of the work of moving your cost. Beyond that it's the proportion — how much petrol was put in against how much your tank takes — and then where the car is and whether a van can get to it safely.
Three queries come first, before quoting, instead of after — what was put in, how much, has it run — and this is the reason. The answers turn a range into a straight figure.
About Credenhill itself
Credenhill is a village in Herefordshire, situated inland at an elevation of 81 metres, approximately 4 miles west of Hereford. Credenhill lies near several notable local landmarks, including Kenchester and Sugwas Pool. Credenhill has a population of around 2024 people, predominantly living in semi-detached housing. Credenhill is located about 121 miles west of London, in the heart of the West Midlands region.
Fuel drain cover across Herefordshire, Credenhill included
Our vans answering petrol in diesel call-outs around Credenhill, in the HR postcode area, equally work the places near it, Kenchester, Sugwas Pool and Stretton Sugwas among them. You need not bring the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots we drain.
In Credenhill and still at the pump?
Then you're in the best spot there is. Turned off it stays; then call.