Harmans Corner: Petrol in a Diesel Car? How Worried to Be
Probably less than you are now — provided nobody has started the car. Until your ignition primes the pump, the starter turns, or the car is driven, petrol in a diesel tank just sits there and does nothing. Which makes the truthful reply to the first Harmans Corner question — "have I ruined it?" — usually no. Leave the motor off then call Petrol in Diesel — that keeps it that way. Below, this page sets out what petrol actually does inside a diesel, how far it might have got, and how to stop it happening to you a second time.
Petrol in a diesel: what does it do to the motor?
Passing through an engine, diesel is doing two jobs at the same time. Oiling comes before burning; it does both. The high-pressure pump and the fuel injectors are made to very fine gaps, and the diesel passing through them is what stops those surfaces from wearing against each other.
Petrol does the first job poorly and the second not at all. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump on the mixture to wear itself. It is equally made to resist igniting under compression — the reverse of what a diesel needs — which is why you hear the rattling.
The shape of the problem is clear when you put those together. It's circulation that does the damage, not contact. Petrol in the tank 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 the fuel to your injectors downstream.
Petrol in a diesel in Harmans Corner: how bad is it? Four situations
Filled but not once started — the best it gets. At a forecourt, and truly only there, that petrol is still confined to your tank — since everywhere else the vehicle was driven to reach it. The task is emptying and flushing on the spot.
A moment's running, or just your ignition on. The system has been primed, so petrol has left that tank and reached the filter and the lines. That's generally still an easy job — a drain, a flush, and the filter seen to.
Those few miles driven meant the pump running on fuel thinned by petrol the whole way. Mileage is only half of it; how hard it was driven counts just as much. Either way this work includes your tank, the lines, the filter and fresh fuel through the entire circuit. Driving the kids to Minterne Junior School is one sort of trip. A run as far as Southend-on-Sea, under 15 miles away, is a very different task. So is any distance on the M2, under 3 miles from Harmans Corner, where the motor has been working hard the whole time.
Driven on until it protested — clattering, smoke, an uneven idle, a soft throttle. That is your engine telling you its fuel no longer is acting like diesel. Stop where you are — on the verge on Washley Hill, at the kerb, down a side road — and do not move it. The fuel drain and flush-through still come first, and they take care of it: when a vehicle is pulled over early, permanent damage is very unusual.
Harmans Corner motorists and that petrol in a diesel stories they hear
False: topping up to full with diesel makes it fine. It does not. Topping up removes nothing; it gives you a fuller tank of the same mix. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance supposes.
If anything, the opposite is true. Myth: "A current diesel can cope with a bit of petrol." A newer diesel sends its fuel through finer components at higher pressure, which makes the lubrication count more, not less.
"It starts, it drives, and so no harm done" — the myth that trips up more drivers than any other. A petrol engine fed diesel normally will not run, so the driver stops and the harm stops with them. A diesel fed petrol generally starts, ticks over and drives away as though nothing has happened, while the pump grinds. Being able to run isn't proof of being fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old workaround, supposed for another fault. It does not put back what petrol has diluted, and that petrol is still in that tank afterwards.
Myth: "Drain your tank yourself and you are sorted." Once the engine has been run, some of the petrol is no longer in your tank: it's in the filter and your lines, and it goes right back through the pump on your next start. Emptying petrol into a can at the roadside is also truly hazardous.
How petrol ends up: petrol in a diesel
It is seldom carelessness, and no one does it on purpose. A diesel nozzle generally won't fit a petrol motor, but the slimmer 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. Courtesy car, hire car, or a motor that's new. Two motors on one driveway, one petrol, one diesel. A forecourt you know, but with its pumps arranged differently. Fuelling up in a rush en route to Sittingbourne, with a train to catch. Years of petrol vehicles behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that's when. Your hand repeats what it has always done once you add rain, a phone call or a back seat full of children.
How to prevent petrol in a diesel on your next fill-up in Harmans Corner
- Green for unleaded and black for diesel is normal in the UK — yet not on every forecourt. Go by the label on the pump, not the colour.
- The first fill in a new vehicle is the time to check the filler flap — inside it, or on the cap, many motors state the fuel they take.
- A coloured fob or a sticker on your diesel's key does more than any amount of intending to remember, for a house with one of each.
- It seems daft and it does the trick: on your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the pump.
- While you're thinking about something else, this is an easy mistake to make — so tuck the phone away.
- Add-on devices are available 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.
- Stop the moment you realise. Less petrol in your tank means a weaker blend. It does not change what to do next, which is still not to start it.
Petrol already in a diesel in Harmans Corner? Begin here
Short and simple, then, is the order of things. Do not turn the ignition on, and do not fire it up. Ask the staff to help you roll it clear of the pump if you are still at the forecourt, whether that's Esso or somewhere else. What went in, roughly how much, and whether it has run: tell us that when you phone 0333 366 0103.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a separate issue — Harmans Corner has a page all for it.
One petrol in a diesel task in Harmans Corner costs more than another. Why?
The four situations above are four separate jobs, so no single price for this would be honest. Which of them you are in is chiefly what moves the cost. Where your car is counts too, and whether our van can safely get to it, after the proportion of petrol to what the tank holds.
What went in, how much, and if it's run — three queries our technicians ask before quoting, not after, for exactly that reason. With the answers, you get a straight figure rather than a range.
About Harmans Corner and where it is
Harmans Corner is a small suburban area in Kent, situated inland at an elevation of 46 metres. Harmans Corner lies near the villages of Borden and Tunstall, and is close to the settlement of Hearts Delight. Harmans Corner is characterized by its predominantly detached housing stock, and is located approximately 14.5 miles from Southend-on-Sea. Harmans Corner is also within commuting distance of London, being around 38 miles from the capital.
Fuel drain cover across Kent, Harmans Corner included
Harmans Corner rests in the ME postcode area, and our vans that answer petrol in diesel call-outs there work the places around it as well — Borden, Hearts Delight and Tunstall among them. We drain wherever your vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
Still at the petrol pump around Harmans Corner?
Then you are in the best position there can be. Turned off it stays; then call.