Beaconsfield: Petrol in a Diesel Car? How Worried to Be
Unstarted? Then less anxious than you likely are. "Have I ruined it?" is the first question everyone around Beaconsfield asks, and the truthful answer is generally no, since petrol left in a diesel tank harms nothing until it is drawn through the system — by ignition priming, by your starter, or by driving. Keep it that way: leave the motor off then ring Petrol in Diesel. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has spread, and ways to make sure you never do it again.
Petrol in a diesel: what does it do to the motor?
Two tasks fall to diesel on its journey through a motor. It combusts, and before it combusts it lubricates. The high-pressure fuel pump and the injectors are designed to extremely fine clearances, and the diesel passing through them is what keeps those surfaces from wearing down against each other.
The second job petrol does not do at all, and the first it does poorly. The rattling comes from petrol being designed not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips away the lubrication the system depends on, and any pump running on that mix is wearing itself.
Put those together and the shape of the trouble is plain. The damage is done by circulation, not by contact. Petrol in a tank is a fuel fault. Whatever a worn pump sheds travels on, borne by the fuel, into the fuel injectors further along, which is why a pump that has worked on the petrol is where a mechanical problem begins.
Four situations our technicians see around Beaconsfield: how bad is petrol in a diesel?
Fuelled but not once started — the best it gets. Just your tank has petrol in it, so the task is draining your tank and flushing your system where your car sits. This situation can only really happen on a forecourt: anywhere else, your car got there by being driven.
A brief spell of running, or just the ignition on. Once primed, the fuel system has drawn petrol out of the tank as far as the fuel filter and the lines. Drain, flush, see to the fuel filter: still normally easy.
Those few miles driven meant the pump running on fuel diluted by petrol throughout. The work is that tank, the lines, your filter and clean fuel through the whole system, and how hard the vehicle was driven counts as much as how far. Driving the kids to St Mary and All Saints CofE Primary School is one kind of trip. Very different a second time: a trip to St Albans, under 25 miles away, or any distance on the M40, under a mile from Beaconsfield, where the motor never stopped working hard.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone lumpy. That is your engine telling you its fuel has stopped behaving like diesel. Stop wherever you are — the verge on Station Road, a lay-by, a side street — and leave the vehicle there. Permanent damage is very unusual if a vehicle is stopped soon, and the drain and flush that still go first take care of it.
What Beaconsfield people get told about petrol in a diesel — and the myths in it
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Nothing comes out when you top up — that tank simply holds more of the same mixture. Percentage isn't how a diesel fuel system copes with petrol, whatever that advice assumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. More precise parts and higher pressure are the way a current diesel runs its fuel, and that makes the protection matter more, not less.
This is the one that catches people. Myth: "If it starts and drives, there's no harm done." Any petrol motor fed diesel generally won't run, and so the driver stops and the damage stops with them. A diesel fed petrol generally starts, ticks over and drives away as though nothing has happened, whilst your pump grinds. Running is not the same as fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It's an old workaround for a distinct fault. None of what petrol weakened is put back by it — and afterwards, the tank still contains that petrol.
The next start sends petrol back round your pump out of the lines and the fuel filter, where some of it sits once the engine has been run. That's why a DIY tank drain does not sort it — a myth. On top of that, petrol drained into a can by the road is genuinely dangerous.
How petrol ends up: petrol in a diesel
No one does it on purpose, and it is seldom carelessness. One way only, because of the nozzles: the narrower petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one generally will not fit a petrol car. That is how the forecourt makes it straightforward.
The moment habit stops matching the car is the moment it happens. Hire cars, courtesy cars, and cars that are new to you. A household with one petrol and one diesel on the driveway. Your usual forecourt, its pumps now in a different order. Filling up in a hurry on the way to the nearest station, with a train to catch. Years of petrol motors behind you, a diesel Volkswagen Passat in front of you on the forecourt for its first tank — that's when. Throw in rain, a phone call or a back seat full of kids, and the hand does what it has always done.
How to avoid petrol in a diesel at your next fill-up around Beaconsfield
- The label is what matters, so check the pump rather than the colour: in the UK unleaded handles are normally green and diesel black, yet not on every forecourt.
- In a vehicle you don't know, look inside the flap over the filler or at the cap before your first fill: many cars state the fuel there.
- A coloured fob or a sticker on your diesel's key does more than any amount of intending to remember, in a household with one of each.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump. It seems daft and it works.
- Mistakes like this are easy to make while your mind is on something else, so your phone goes away.
- Some diesels have a filler built to block a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump.
- Stop the moment you realise. Less petrol in that tank means a weaker mix. It does not change what to do next, which is still not to crank it.
Put petrol in a diesel around Beaconsfield already?
Then the order of things is brief. Do not switch your ignition on, and don't fire it up. If you're still at the forecourt — Esso or anywhere else — ask the attendants to help you roll it clear of the petrol pump. Then phone 0333 366 0103 and tell us what got in, roughly how much, and if it's run.
Say so if it was AdBlue instead of petrol: it is a different issue, with its own page for Beaconsfield, because AdBlue brings corrosion and deposits rather than lost lubrication.
One petrol in a diesel job in Beaconsfield costs more than another. Why?
There is no honest single quote for this, since the four situations above are four different tasks. Chiefly, your cost shifts with which situation you're in. Where the car is matters too, and whether a van can safely get to it, after the share of petrol to what that tank holds.
Before any quote, not after, come three questions: your fuel that was put in, its amount, and if it's run. That's why. A range turns into a straight figure once those answers are in.
About Beaconsfield and where it is
Beaconsfield is a town in south Buckinghamshire, situated approximately 23 miles west of London and 16 miles southwest of St Albans. Beaconsfield sits in a valley at an elevation of around 107 metres, surrounded by the Chiltern Hills and nearby villages such as Knotty Green and Forty Green. Beaconsfield is characterised by its predominantly detached housing stock and a population of around 11,400 residents. Beaconsfield benefits from its proximity to the M40 motorway and mainline railway to London.
Fuel drain cover across Buckinghamshire, Beaconsfield included
The vans answering petrol in diesel calls around Beaconsfield, in the HP postcode area, also work the locations near it, Knotty Green, Forty Green and Holtspur included. We drain where your vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
In Beaconsfield and still at the pump?
The best spot there is, then — that's where you are. Keep it off. Call.