Should You Worry? Petrol in a Diesel Car in Daventry
Not started? Then less anxious than you probably are. "Have I ruined it?" is the first thing everyone in Daventry asks, and the truthful answer is usually no, since petrol left in a diesel tank harms nothing till it is dragged through your fuel system — by ignition priming, by the starter, or by driving. Keep it that way: leave the motor off then ring Petrol in Diesel. The remainder of this page covers what petrol actually 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.
What petrol in a diesel does to the motor
On its way through an engine, diesel does two tasks. Before it combusts, it protects — and then it burns. Your high-pressure pump and the injectors are built to extremely fine gaps, and the diesel passing through them is what stops those surfaces from grinding against each other.
Of these two jobs, petrol manages the first badly and the second never. A pump working on a petrol mixture is wearing itself out, since petrol is runnier than diesel and strips out the lubrication the fuel system depends on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that's where any rattling starts.
Combined, those leave the shape of the issue plain. The damage is done by circulation, not by contact. A tank with petrol in it is a fuel problem. Whatever a worn pump sheds goes on, carried by your fuel, into your injectors downstream, which is why a pump that has been working on that petrol is where a mechanical issue starts.
Daventry, petrol in a diesel: four situations, from mild to significant
Filled up, and never started: nothing beats it. The petrol is inside 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 take place on a forecourt, because anywhere else your car has been driven to get there.
A brief spell of running, or merely your ignition on. Petrol has come out of your tank and got to the fuel filter and the lines, since your system has been primed. That is normally still an easy task — a drain, a flush, and the filter dealt with.
Your pump has spent a couple of miles on thinned fuel — that is what driving it does. The work is that tank, the lines, the fuel filter and fresh fuel through the entire system, and how hard the vehicle was driven counts as much as how far. The school run to Abbey CofE Academy is one matter. A run as far as Coventry, under 25 miles away, is a very different task. So is any distance on the M1, under 3 miles from Daventry, where the motor has been working hard throughout.
It protested, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone lumpy. The motor is telling you your fuel is no longer behaving like diesel. Stop wherever you are — the verge on Abbey Street, a lay-by, a side street — and leave the car there. What comes first is still the fuel drain and flush, and that sorts it out, with long-term damage very uncommon when a vehicle is pulled over quickly.
Daventry motorists and the petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Nothing is removed by topping up — you are left with a fuller tank, still the same mix. Percentage isn't how a diesel fuel system tolerates petrol, however much that advice presumes.
If anything, the opposite holds. Myth: "A newer diesel can cope with a bit of petrol." At higher pressure, through more precise parts: that is how a newer diesel moves its fuel, so the protection counts for more, not less.
This is the one that catches motorists. Myth: "If it starts and drives, there is no damage done." The driver of a petrol motor fed diesel normally stops, since it will not run, and the harm stops there. Whilst your pump grinds, a diesel fed petrol normally starts, idles and drives away as if nothing has happened. Running is not the same as fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old workaround, meant for another fault. It doesn't put back what petrol has weakened, and the petrol is still in the tank after that.
Myth: "Drain the tank yourself and you're sorted." Once the engine has run, some of that petrol is no longer in your tank: it's in the filter and the lines, and it goes right back through the pump on your next start. Also, a can of petrol drained by the kerbside is truly risky.
Petrol in a diesel: how does it take place?
Nobody does it on purpose, and it is rarely carelessness. The petrol nozzle is the slimmer of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol car at all. The forecourt makes it easy, and the mistake runs one way.
It happens when routine and the vehicle stop matching. A new vehicle, a hire car or a courtesy car. A household with one petrol and one diesel on the driveway. A forecourt you know, but with its pumps laid out differently. Racing for a train outside Long Buckby and fuelling up en route. Exactly the moment it takes place: after years of driving petrol, a driver fills a diesel Volkswagen Passat for the first time. Add a back seat full of kids, a phone call or rain, and habit wins.
Avoiding petrol in a diesel next time you fill up around Daventry
- Check the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, but not on every forecourt. The label is what counts.
- Inspect the filler flap. Plenty of cars state the fuel type inside the flap or on the cap. Look at it on the first fill in any vehicle you don't know.
- A coloured fob or a sticker on the diesel's key does more than any amount of intending to remember, in a house with one of each.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It sounds daft and it works.
- Thinking about something else is when this becomes an easy mistake to make, so tuck the phone away and keep your mind on the pump.
- Some diesels come with a filler built to refuse a petrol nozzle, and devices you can add are available for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the pump.
- Noticing it halfway? Stop at once. A thinner mix results from less petrol inside your tank, but the next stage remains the same: do not crank it.
Already put petrol in a diesel around Daventry?
In that case, there is only a short order of things. Leave it unstarted, with the ignition switched off too. If you're still on the forecourt — Esso or anywhere else — ask the attendants to help you roll the car away from the petrol pump. Ring 0333 366 0103 next, with three facts — your fuel, the approximate quantity, and whether it's run.
Say so if it was AdBlue rather than petrol: it is a different problem, with its own page for Daventry, because AdBlue brings corrosion and deposits rather than lost protection.
Why one petrol in a diesel task in Daventry costs more than another
Four different tasks lie behind the four situations above — which is why there's no honest single price. Chiefly, your cost moves with which situation you're in. The ratio counts next, meaning how much of that tank is petrol, and then the position of the vehicle and whether reaching it is safe for our van.
What went in, how much, and whether it's run — three questions our technicians ask before costing, not after, for exactly that reason. The replies change a range into a straight figure.
About Daventry itself
Daventry is a town in Northamptonshire, situated on the shores of Daventry Reservoir, a lakeside setting that provides recreational opportunities for residents. Daventry sits at an elevation of around 150 metres, approximately 68 miles northwest of London, and is close to nearby places such as Drayton, Newnham, and Norton. Daventry has a population of around 18,760 people, predominantly living in semi-detached housing. Daventry is located near the city of Coventry, which is about 18 miles away.
Across Northamptonshire and around Daventry: fuel drain cover
Petrol in diesel calls around Daventry — part of the NN postcode area — go to vans that likewise cover the places round it, Drayton, Newnham and Norton among them. We drain wherever the vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Still at the petrol pump around Daventry?
Nothing beats it: that's where you now are. Turned off it stays; then ring.