How Worried Should You Be? Petrol in a Diesel Car in Alderholt
Probably less than you are now — as long as nobody has started it. "Have I wrecked it?" is the first question everyone in Alderholt asks, and the honest answer is normally no, since petrol left in a diesel tank harms nothing till it's drawn through the system — by ignition priming, by your starter, or by being driven. Leave the engine off and call Petrol in Diesel — that is how you keep it that way. The rest of this page explains what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you a second time.
Inside the motor: what petrol in a diesel really does
Two jobs fall to diesel on its route round a motor. Before it burns, it protects — and then it burns. Extremely fine tolerances go into the fuel injectors and the high-pressure pump, and only your diesel flowing through keeps those surfaces from grinding together.
Badly at the first, not at all at the second: that is petrol. The knocking comes from petrol being designed not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips out the protection the fuel system rests on, and any pump running on that blend is wearing itself.
Put these together and the shape of the problem is clear. Contact doesn't do the harm — movement does. All a tank with petrol in it amounts to is a fuel fault. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with the fuel to your injectors downstream.
Four scenarios we see in Alderholt: how bad is petrol in a diesel?
Fuelled, and not started: nothing beats it. Being on a forecourt is what makes this possible: elsewhere, the car has been driven there to begin with. With the petrol kept inside the tank alone, it is cleared and purged on the spot, and nothing more is needed.
A brief spell of running, or just the ignition on. With your system primed, the fuel lines and filter now hold petrol that came from that tank. Drain, flush, see to the filter: still normally simple.
The pump now spent a few miles on diluted fuel — that is what driving the car does. How hard your car was driven matters as much as how far, and the work takes in the tank, the fuel lines, the filter and clean fuel through the whole circuit. Driving the children to St James' Church of England First School and Nursery, Alderholt is one kind of trip. A run as far as Salisbury, under 15 miles away, is a very different task. So is any miles on the M27, under 15 miles from Alderholt, where the engine has been labouring hard the whole time.
Clattering, an uneven idle, smoke, a throttle gone soft: driven till it complained. The engine is telling you your fuel is no longer acting like diesel. Pull up where you are — on the verge on Daggons Road, at the kerb, down a side road — and do not move it. A vehicle stopped quickly very rarely has permanent damage, since the drain and the flush, which still come first, sort it out.
What Alderholt people get told about petrol in a diesel — and the stories in it
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Nothing is removed when you top up — your tank simply holds more of the same mixture. A diesel fuel system does not tolerate petrol by percentage in the way that advice presumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. Protection matters more on modern diesels, not less, because their fuel runs through finer components at higher pressure.
One myth that catches motorists off guard: if it starts and drives, it must be unharmed. Diesel in a petrol motor usually leaves a motor that won't run: the driver stops, and so does the damage. Whilst your pump wears, a diesel fed petrol normally starts, idles and drives away as though nothing has happened. Running doesn't mean fine.
Myth: "Add some two-stroke oil and drive it home." It is an old fix for a different problem. That petrol is still inside your tank after that, and whatever it has diluted is not put back.
The next start sends petrol back round the pump out of the fuel lines and the filter, where some of that sits once your engine has run. That is why a DIY tank drain does not sort it — a myth. It's also really hazardous to drain petrol into a can by the roadside.
Why petrol in a diesel occurs so easily
A careless moment is rarely 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 generally will not go into a petrol vehicle at all. The forecourt makes it easy, and the slip runs one way.
The moment habit stops matching the vehicle is the moment it takes place. Courtesy car, hire car, or a vehicle that is brand new. Households running one of each, petrol and diesel. A forecourt you know, but with its pumps arranged differently. A train to catch, and a hurried fill en route to Salisbury. A new-to-you diesel Volkswagen Golf, its first fuelling, and a motorist accustomed to petrol: precisely when it occurs. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of kids.
Next time you fill up around Alderholt: avoiding petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Read the petrol pump's label; the colour is just a hint.
- Many motors state the fuel inside the filler flap or on the cap, so check it on your first fill in any car you do not know.
- One of each in the house? Mark the key to the diesel — a bright fob, a sticker — since meaning to remember is not enough.
- It seems silly and it does the trick: on the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump.
- Mistakes like this are simple to make while your mind is on something else, so the phone goes away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to block a petrol nozzle, and aftermarket devices are available for the remainder. Count it as a safety net, and keep checking the petrol pump.
- Spotting it halfway? Stop at once. A thinner blend follows from less petrol inside your tank, but your next stage stays the same: do not fire it up.
Already put petrol in a diesel in Alderholt?
Then, there's just a short order of things. Do not crank it, and don't switch your ignition on. Ask the attendants to help you roll it away from the petrol pump if you're still at the forecourt, whether that's Harvest Energy or anywhere else. Next, 0333 366 0103. We'll ask what went in, about how much, and if it's been run.
If it was AdBlue instead of petrol, say so. That's a separate issue — corrosion and deposits rather than lost lubrication — and it has its own page for Alderholt.
Alderholt petrol in a diesel tasks: why one costs more than another
A fair single price doesn't exist here: four situations, four separate jobs. Which of them you are in is mostly what moves the cost. Where the vehicle is counts too, and whether our van can safely get to it, after the proportion of petrol to what the tank takes.
That's why we ask three questions before pricing rather than after: what got in, how much, and whether it has run. Their answers are what change a range into one firm number.
About Alderholt and its setting
Alderholt is a village in Dorset, situated on the shores of a lake at an elevation of 54 metres, and is characterised by its predominantly detached housing stock. Alderholt lies near the villages of Camel Green, Daggons, and Lower Daggons, and is approximately 11 miles from the city of Salisbury. Alderholt has a population of around 1328 residents and is located in a rural setting. Alderholt is also within commuting distance of London, being around 84.7 miles away.
Fuel drain cover around Alderholt and across Dorset
Alderholt sits in the SP postcode area, and our teams that answer petrol in diesel calls there work the spots near it as well — Camel Green, Daggons and Lower Daggons among them. No need to bring the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own drive are all places where we work.
At the petrol pump in Alderholt, right now?
No position is better: that is where you are. Keep it off. Call.