How Worried Should You Be? Petrol in a Diesel Car in Knowle
If it hasn't been started, worry less than you likely are. Everyone in Knowle begins with "have I wrecked it?", and the fair answer is usually no: petrol resting in your tank of any diesel remains harmless until priming, cranking or driving pulls it into your fuel system. Petrol in Diesel is who to call, with your motor kept off, so it stays that way. Read on for three things: the effect petrol has inside a diesel engine, the signs of how far it has got, and ways to make sure you never do it again.
What petrol in a diesel does to the engine
Two tasks fall to diesel on its route round a motor. Before it burns, it lubricates — then it combusts. What stops the surfaces inside your high-pressure pump and the fuel injectors from wearing against each other is the diesel flowing through them — they're made to very fine tolerances.
Of those two jobs, petrol handles the first poorly and the second never. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, leaving a pump on that mixture to wear itself. It is also made to resist igniting under compression — the opposite of what a diesel needs — which is why you get the rattling.
Together, those leave the shape of the trouble clear. Contact doesn't do the harm — circulation does. All a tank with petrol in it amounts to is a fuel fault. 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 the fuel to your injectors downstream.
Four scenarios we see around Knowle: how bad is petrol in a diesel?
Fuelled up, never started. The best case there is. The petrol is in the tank and just that tank, and the task is a drain and a flush where the vehicle stands. This is the one situation that can only truly take place on a forecourt, since anywhere else the vehicle has been driven to get there.
Ignition on, or started for a second. Petrol has come out of that tank and got to the fuel filter and the lines, because the system has been bled. Drain, flush, deal with your filter: still normally easy.
A few miles driven, and the pump has spent each of them working on diluted fuel. The work is the tank, the fuel lines, your filter and clean fuel through the entire system, and how hard your car was driven counts as much as how far. On the school run to Knowle Church of England Primary Academy, the mileage is small. Very different again: a trip to Birmingham, under 10 miles away, or any distance on the M42, under 3 miles from Knowle, where your engine kept running hard.
Driven till it complained. Rattling, an uneven idle, smoke, a throttle that has gone soft. What you are hearing is your motor reporting fuel that no longer acts like diesel. Stop wherever you are — the verge on High Street, a lay-by, a side street — and leave the car there. A car stopped quickly very rarely has lasting damage, since the drain and the flush-through, which still come first, take care of it.
Petrol in a diesel myths Knowle people 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. That advice presumes a diesel fuel system tolerates petrol by percentage. It doesn't.
If anything, the reverse is true. Myth: "A newer diesel can cope with a bit of petrol." At higher pressure, through smaller components: that is how a modern diesel handles its fuel, so the protection counts more, not less.
This is the one that catches people. Myth: "If it starts and drives, there is no harm done." The driver of a petrol motor fed diesel usually has no choice but to stop, since it will not run, and the damage stops there. A diesel fed petrol generally starts, idles and drives away as though nothing has happened, whilst the pump wears. Running does not mean fine.
Myth: "Add some two-stroke oil and drive the car home." It is an outdated fix for a distinct fault. None of what petrol diluted is put back by it — and afterwards, that tank still contains that petrol.
Once your engine has run, part of that petrol is in the fuel filter and the lines, not the tank — and the next start sends it right back through the pump. So the myth "drain that tank yourself and you are sorted" does not stand up. On top of that, petrol cleared into a can by the road is genuinely risky.
How petrol ends up: petrol in a diesel
It is rarely carelessness, and no one does it on purpose. The petrol nozzle is the smaller of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol motor at all. The forecourt makes it simple, and the error runs one way.
Habit and the vehicle getting out of step is when it takes place. Courtesy car, hire car, or a vehicle that's new. Two vehicles on one drive, one petrol, one diesel. A forecourt you know, but with its pumps laid out differently. Filling up in a rush on the way to Dorridge, with a train to catch. Precisely the moment it occurs: after years of driving petrol, a driver fills a diesel Volkswagen Passat for the first time. With rain, a call coming in, or children to deal with, the hand simply does what it has always done.
Avoiding petrol in a diesel next time you fill up around Knowle
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most usually do. Check the pump's label; the colour is just a clue.
- In a car you do not know, look inside the flap over your filler or at the cap before the first fill: many vehicles print the fuel type there.
- One of each in the house? Label your key to the diesel — a bright fob, a sticker — because intending to remember isn't enough.
- It seems silly and it works: on your first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck your phone away and keep your mind on the pump.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to block a petrol nozzle, and aftermarket devices exist for the rest. Treat it as a backstop, and keep checking the petrol pump.
- Stop as soon as you realise. Less petrol in that tank means a thinner blend. It does not change what to do next, which is still not to crank it.
Petrol already in a diesel in Knowle? Begin here
Short and simple, then, is the order of things. Don't fire it up, and do not turn the ignition on. The staff on the forecourt — whether at Esso itself or wherever you filled up — will normally help roll it clear of the petrol pump if you ask. Call 0333 366 0103 next, with three facts — the fuel, the rough amount, and if it has run.
If it was AdBlue instead of petrol, say so. That is a separate fault — corrosion and deposits instead of lost lubrication — and it has its own page for Knowle.
What makes one Knowle petrol in a diesel job cost more than the next
There is no honest single price for this, because the four scenarios above are four separate tasks. Which of them you are in is mostly what shifts your cost. Where the vehicle is counts too, and whether a van can safely reach it, after the ratio of petrol to what your tank takes.
That's why our technicians ask three questions before quoting instead of after: what was put in, how much, and whether it has run. Those replies are what change a range into one firm number.
About Knowle and its setting
Knowle is a village situated in the West Midlands, on the banks of a river, with an elevation of around 129 metres. Knowle lies approximately 9.5 miles southwest of Birmingham and 91.6 miles northwest of London. Knowle has a mix of housing types, but semi-detached homes are particularly prevalent in the area. Knowle is surrounded by nearby places such as Tilehouse Green, Rotten Row, and Knowle Grove.
Fuel drain cover across West Midlands, Knowle included
Knowle rests in the B postcode area, and the teams that answer petrol in diesel call-outs there work the locations near it as well — Tilehouse Green, Rotten Row and Knowle Grove among them. You need not move the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places we drain.
In Knowle and still at the pump?
The best position there is, then — that is where you are. Keep it off. Call.