How Worried Should You Be? Petrol in a Diesel Car in Snodland
If it hasn't been started, you can worry less than you probably are. "Have I wrecked it?" is the first thing everyone around Snodland asks, and the honest answer is generally no, since petrol left in a diesel tank harms nothing till it is drawn through the fuel system — by ignition priming, by your starter, or by being driven. To leave it that way, call Petrol in Diesel then leave your engine alone. Read on for three things: the effect petrol has inside a diesel engine, the signs of how far it has got, and the way 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 route through a motor. Before it ignites, it lubricates — and then it burns. Very fine clearances are built into the injectors and the high-pressure pump, and only the diesel running through stops their surfaces grinding together.
The second job petrol doesn't do at all, and the first it does poorly. A pump running on a petrol mixture is wearing itself out, because petrol is runnier than diesel and strips out the lubrication your fuel system relies on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that's where any rattling comes.
The shape of the problem is clear once you put those together. It is movement that does the harm, not contact. Petrol in a tank is a fuel problem. 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 your fuel to the injectors further on.
Petrol in a diesel in Snodland: how serious is it? Four cases
Filled up, and not started: no case is better. The petrol is in that tank and only your tank, and the task is a drain and a flush where the vehicle stands. This is the one scenario that can only really take place on a forecourt, because anywhere else the car has been driven to get there.
Ignition on, or started for a second. The system has been bled, so petrol has left that tank and got to your filter and the lines. Drain, flush, deal with the filter: still normally straightforward.
A few miles driven, and the pump has spent every one of them labouring on thinned fuel. How hard the car was driven matters as much as how far, and the work takes in the tank, the fuel lines, your filter and fresh fuel through the entire circuit. Short trips, such as the school run to Valley Invicta Primary School at Holborough Lakes, are one matter. A run as far as Southend-on-Sea, under 25 miles away, is a very different task. So is any distance on the M20, under 3 miles from Snodland, where your engine has been labouring hard the whole time.
Driven on until it complained — rattling, smoke, a lumpy idle, a dead throttle. The fuel is not behaving like diesel any more, and your engine is telling you. Whether it's the verge on Malling Road, a lay-by or a side road, stop there then leave it. A vehicle stopped soon very seldom has lasting damage, since the drain and the flush-through, which still go first, take care of it.
Stories Snodland motorists hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Nothing is removed when you top up — the tank simply holds more of the same mixture. Percentage isn't how a diesel fuel system copes with petrol, however much that guidance assumes.
If anything, the reverse is true. Myth: "A current diesel can cope with a bit of petrol." At higher pressure, through more precise parts: that's how a current diesel moves its fuel, so the lubrication counts for more, not less.
"It starts, it drives, and so there is no harm" — the myth that trips up most motorists than any other. The driver of a petrol engine fed diesel usually stops, because it will not run, and the harm stops there. A diesel fed petrol normally starts, ticks over and drives away as if nothing has happened, whilst your pump wears. Running isn't the same as fine.
Myth: a two-stroke additive lets you to drive home. It is an old workaround, meant for another fault. It does not put back what petrol has weakened, and that petrol is still inside that tank afterwards.
Myth: "Drain that tank yourself and you're sorted." After the engine has run, some of the petrol is no longer inside your tank: it is in your filter and the fuel lines, and it goes straight back through your pump at the next start. On top of that, petrol drained into a can by the road is genuinely risky.
Petrol in a diesel: how does it happen?
It is seldom carelessness, and nobody does it on purpose. A diesel nozzle mostly will not fit a petrol vehicle, but the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake straightforward, and only in one direction.
When habit and the car stop matching, it occurs. A new car, a hire car or a courtesy car. Two motors on one driveway, one petrol, one diesel. The pumps in a different order on a well-known forecourt. Fuelling up in a hurry on the way to the nearest station, with a train to catch. Exactly the moment it occurs: after years of driving petrol, a driver fills a diesel Audi A4 for the first time. Add a back seat full of kids, a phone call or rain, and the hand wins.
Preventing petrol in a diesel next time you fill up in Snodland
- The label is what matters, and so check the petrol pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on each forecourt.
- In a motor you do not know, look inside the flap over your filler or at the cap before the first fill: plenty of cars state the fuel type there.
- Good intentions count for less than a sticker or a fob in a vivid colour on the diesel's key if a house has one of each. So mark it.
- "Diesel", aloud, before you lift the nozzle — each time a new or hired car needs its first tank. It seems daft. It does the trick.
- Mistakes like this are easy to make while your mind is on something else, so your phone goes away.
- Some diesels have a filler designed to reject a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the pump.
- Less petrol means a weaker blend, and so stop the moment you realise — while remembering that your next step is unchanged. It's still not to start the vehicle.
Put petrol in a diesel in Snodland already?
Short and simple, then, is the order of things. Don't switch your ignition on, and do not crank it. If you are still on the forecourt — BP or anywhere else — ask the attendants to help you roll it away from the pump. Next, 0333 366 0103. We'll ask what went in, about how much, and if it has been run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a different issue — Snodland has a page just for it.
One petrol in a diesel job around Snodland costs more than another. Why?
Four different jobs sit behind the four situations above — which is why there's no honest single quote. Chiefly, the cost shifts with which one you are in. Two things come after that: the petrol that got in as a share of what the tank takes, then the place the car is in and whether our van can get to it safely.
Ahead of any quote, not after, come three questions: your fuel that got in, its quantity, and if it has run. That is why. With the replies, you get a straight figure instead of a range.
About Snodland and its setting
Snodland is a town situated on the River Medway in Kent, with a population of around 12208 people. Snodland has a mix of housing types, but semi-detached homes are predominant, and the town's elevation is approximately 13 metres above sea level. Snodland is located near several nearby places, including Holborough, Ham Hill, and Burham Court, and is within commuting distance of London, about 27.5 miles away. Snodland sits on the riverside, close to the confluence of the Medway and its tributaries.
Snodland and Kent: where our fuel drain cover runs
Petrol in diesel calls around Snodland — part of the ME postcode area — go to teams that likewise cover the locations around it, Holborough, Ham Hill and Burham Court included. The car does not need to move to us: our engineers drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Still at the pump around Snodland?
Then you are in the best position there can be. Switched off it stays; then ring.