Petrol in a Diesel Car in Penge: How Worried Should You Be?
Far less than you probably are, provided it hasn't been started. Petrol resting in a diesel tank does nothing to the motor till something draws it through the fuel system — the ignition priming the pump, the starter, or the drive on its own. So the fair answer to the first query anyone around Penge asks, "have I wrecked it?", is usually no. Petrol in Diesel is who to call, with your motor left off, so it stays that way. Keep reading for three things: the effect petrol has inside a diesel engine, the clues of how far it has spread, and the way to make sure you don't do it again.
Petrol in a diesel: what does it do to the engine?
On its way through an engine, diesel has two tasks. Before it combusts, it protects — and then it ignites. What keeps the surfaces inside the high-pressure fuel pump and your injectors from wearing down against each other is your diesel flowing through them — they're built to extremely fine clearances.
Petrol does the first job poorly and the second not at all. A pump working on a petrol blend is wearing itself out, because petrol is runnier than diesel and takes away the protection your fuel system depends on. Petrol is also made to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that is where any knocking starts.
The shape of the issue is clear when you put those together. Not contact but circulation is what does the damage. Where the petrol is only in your tank, it's a problem of fuel, nothing more. Once your pump has been running on that petrol, a mechanical fault has started: anything shed by a pump that is wearing down is carried downstream to your injectors with the fuel.
Petrol in a diesel around Penge: how bad is it? Four cases
The best case there is: filled up, never started. That petrol is inside that tank and just the tank, and the job is a drain and a flush where your car sits. This is the one scenario that can only truly take place at a forecourt, because anywhere else the car has been driven to get there.
Started for a second, or just the ignition on. Petrol has come out of the tank and got to your filter and the fuel lines, because the fuel system has been primed. That is generally still a simple job — a drain, a flush, and your filter dealt with.
Your pump has spent a few miles on weakened fuel — that's what driving it does. Mileage is only half of it; how hard it was driven counts just as much. Either way the work includes the tank, your lines, the filter and clean fuel through the entire system. On the school run to St John's Church of England Primary School, the distance is short. Driving as far as Westminster, under 10 miles away, makes a very different job — as does any miles on the M25, under 10 miles from Penge, with the motor working hard all the way.
Driven on until it complained — knocking, smoke, a lumpy idle, a soft throttle. That is the motor telling you its fuel no longer is behaving like diesel. Leave it wherever it has stopped: a lay-by, a quiet street, the verge on Penge Lane. The fuel drain and flush-through still go first, and they sort it out: when a car is pulled over soon, lasting damage is very uncommon.
Stories Penge drivers hear about petrol in a diesel
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Topping up removes nothing; it gives you a fuller tank of the same mix. The idea behind that advice — that diesel fuel systems accept petrol by percentage — is wrong.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the opposite. Smaller parts and higher pressure are the way a current diesel runs its fuel, and that makes the protection matter more, not less.
"It starts, it drives, and so no harm done" — the myth that catches most motorists than any other. Feed diesel to a petrol motor and it generally will not run, so the motorist stops — and the damage stops with them. A diesel fed petrol generally starts, ticks over and drives away as if nothing has happened, while the pump grinds. Fine and running are not the same thing.
Myth: "Add some two-stroke oil and drive the vehicle home." It is an outdated fix for a separate problem. What petrol has thinned remains thinned, and the petrol remains inside the tank anyway.
The next start draws petrol back round the pump out of the fuel lines and the filter, where some of that ends up after the engine has been run. That is why draining your tank yourself does not sort it — a myth. It's also really risky to drain petrol into a can at the kerbside.
How does petrol in a diesel take place?
Nobody does it on purpose, and it's rarely carelessness. The forecourt makes it easy: the petrol nozzle is the smaller of the two, and it slips into a diesel filler with almost no resistance, whilst a diesel nozzle generally will not go into a petrol vehicle at all. So the slip runs one way.
Habit and your car getting out of step is when it takes place. Any car that is new to you — a hire car, on loan as a courtesy car, or brand new. Two vehicles on one drive, one petrol, one diesel. The pumps in a different order on a well-known forecourt. A train to catch, and a rushed fill on the way to Penge East. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is exactly the moment it takes place. Add rain, a phone call or a back seat full of kids, and the hand does what it has always done.
Penge people: how to avoid petrol in a diesel next time
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most usually do. Check the petrol pump's label; the colour is just a hint.
- Check your filler flap. Many cars state the fuel inside the flap or on the cap. Look at it on your first fill in any car you don't know.
- One of each in the household? Mark the key to the diesel — a coloured fob, a sticker — since meaning to remember isn't enough.
- "Diesel", aloud, before you pick up the nozzle — each time a new or hired car needs its first tank. It sounds silly. It does the trick.
- Mistakes like this are simple to make whilst your mind is on something else, and so the phone goes away.
- Add-on devices are available for cars without one, and some diesels are built with a filler that will not take a petrol nozzle. Useful — but a safety net only, never a reason to stop checking the label.
- The moment you notice, stop: less petrol in your tank makes a thinner mix. What to do next doesn't change, though — still do not crank it.
Petrol already in a diesel in Penge? Start here
Then the order of things is short. Starting it is out, and so is switching on your ignition. If you're still on the forecourt — JET or anywhere else — ask the attendants to help you roll the car clear of the petrol pump. Call 0333 366 0103 next, with three facts — the fuel, the approximate volume, and if it's run.
Corrosion and deposits are the issue with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and see its own Penge page.
What makes one Penge petrol in a diesel task cost more than the next
Four separate jobs lie behind the four scenarios above — which is why there is no fair single price. What shifts your cost is chiefly which of them you're in. After that it is the proportion — how much petrol got in against how much that tank holds — and after that where the car is and whether a van can reach it safely.
Ahead of any quote, not after, come three questions: the fuel that went in, the quantity, and whether it has run. That's why. The answers turn a range into a straight figure.
About Penge, for a moment
Penge is a locality in south London, situated near the River Effra and the Crystal Palace area. Penge sits at an elevation of 37 metres, approximately 7 miles from central London, and is surrounded by other localities such as Anerley and Sydenham. Penge is predominantly composed of flat dwellings, reflecting its urban character. Penge has a population of around 8091 residents, according to recent estimates.
Fuel drain cover in Penge and across Greater London
Petrol in diesel calls around Penge — part of the SE postcode area — go to vans that also cover the spots about it, Anerley, Sydenham and Elmers End among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all spots our technicians work, and your car does not need to come to us.
At the pump in Penge, still?
The best place there is, then — that's where you are. Ring, and keep it turned off.