Mount Hill: Petrol in a Diesel Car? How Worried to Be
If it hasn't been started, worry less than you probably are. Everyone in Mount Hill starts with "have I wrecked it?", and the fair answer is normally no: petrol left inside that tank of a diesel remains harmless until priming, cranking or driving pulls it into the fuel system. Keep it like that: leave your engine off then phone Petrol in Diesel. Further down, you will find what petrol really does inside a diesel, how far it may have gone, and how to stop it happening to you again.
Petrol in a diesel: what does it do to the engine?
Passing through an engine, diesel does two jobs at the same time. Oiling comes before burning; it does both. Extremely fine tolerances are built into your injectors and your high-pressure pump, and only the diesel flowing through stops their surfaces grinding together.
Petrol handles the first task poorly and the second not at all. The clattering comes from petrol being made not to ignite when compressed, which is exactly the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips out the lubrication the fuel system hinges on, and any pump running on such a blend is wearing itself.
Put those together and the shape of the problem is plain. Not contact but circulation is what does the harm. A tank with petrol in it is a fuel problem. Whatever a worn pump sheds travels on, borne by your fuel, into your injectors downstream, which is why a pump that has worked on that petrol is where a mechanical fault begins.
Mount Hill, petrol in a diesel: four cases, from mild to major
Fuelled but not once started — as good as it gets. On a forecourt, and really only there, that petrol is still confined to the tank — because anywhere else your car was driven to reach it. The task is emptying and flushing on the spot.
A brief spell of running, or merely the ignition on. With the fuel system primed, the lines and filter already hold petrol that has come from the tank. That is usually still an easy task — a drain, a flush, and the filter dealt with.
Driven a couple of miles. Now your pump has spent those miles labouring on weakened fuel. Distance is only half of it; how hard it was driven matters just as much. Either way the work includes that tank, your lines, the fuel filter and fresh fuel through the whole circuit. On the school run to Beacon Rise Primary School, the distance is small. A run as far as Bristol, under 5 miles away, is a very different task. So is any distance on the M32, under 3 miles from Mount Hill, where the engine has been working hard throughout.
Driven until it complained. Rattling, an uneven idle, smoke, a throttle that has gone soft. The engine is telling you your fuel is no longer behaving like diesel. Stop on the spot — on the verge on Mount Hill Road, at the kerb, down a side road — and don't move it again. The fuel drain and flush-through still go first, and they take care of it: if a vehicle is pulled over early, long-term damage is very rare.
Mount Hill motorists and the petrol in a diesel myths they hear
False: topping up to full with diesel makes it fine. It doesn't. Nothing is removed by topping up — you are left with a bigger tank, still the same mixture. The idea behind the advice — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the opposite holds. Myth: "A modern diesel can cope with a bit of petrol." Lubrication matters more on newer diesels, not less, since their fuel runs through more precise components at higher pressure.
Myth: "If it starts and drives, there's no harm done." This is the one that fools people. Feed diesel to a petrol motor and it normally won't run, and so the motorist stops — and the damage stops with them. Whilst your pump grinds, a diesel fed petrol normally starts, idles and drives away as though nothing has happened. Running isn't the same as fine.
An outdated fix for a separate issue lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has diluted remains thinned, and the petrol remains in your tank anyway.
If your engine has run, part of the petrol is in the fuel filter and the fuel lines, not your tank — and the next start pulls it right back through the pump. So the myth "drain the tank yourself and you're sorted" doesn't hold. And, a can of petrol filled by the roadside is genuinely hazardous.
Petrol in a diesel: how does it happen?
On purpose? Never. Through carelessness? Rarely, if ever. The petrol nozzle is the slimmer of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol motor at all. The forecourt makes it easy, and the error runs one way.
Habit and the vehicle falling out of step is when it occurs. A new car, a hire car or a courtesy car. Two vehicles on one driveway, one petrol, one diesel. A well-known forecourt with the pumps in a different order. A train to catch, and a hurried fill en route to Keynsham. A new-to-you diesel Renault Megane, its first fuelling, and a motorist accustomed to petrol: precisely when it happens. Throw in rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
Avoiding petrol in a diesel next time you fill up around Mount Hill
- A green handle for unleaded and black for diesel is usual in the UK — but not on each forecourt. Trust the label on the pump, not the colour.
- Many cars state the fuel inside your filler flap or on the cap, and so check there on the first fill in a motor you don't know.
- Label the key. In a home with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- It seems silly and it works: on the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump.
- Thinking about something else is when this becomes an easy mistake to make, so put the phone away then keep your mind on the petrol pump.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to reject a petrol nozzle, and aftermarket devices exist for the rest. Count it as a safety net, and keep reading the petrol pump.
- As soon as you realise, stop: less petrol inside the tank makes a weaker blend. What to do next does not change, though — still don't start it.
Already put petrol in a diesel in Mount Hill?
Then, there's only a short order of things. Do not turn the ignition on, and do not crank it. Yet on the forecourt, at Asda or anywhere else? Ask the attendants to help you roll the car clear of the petrol pump. What went in, about how much, and whether it has run: tell us that when you ring 0333 366 0103.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a different problem — Mount Hill has a page just for it.
One petrol in a diesel task in Mount Hill costs more than another. Why?
There is no fair single quote for this, since the four situations above are four separate tasks. Chiefly, the cost moves with which one you are in. After that it's the ratio — how much petrol was put in against how much that tank takes — and after that where your car is and whether a van can reach it safely.
Before any quote, not after, come three queries: your fuel that was put in, its quantity, and if it's run. That is why. A range becomes a straight figure once those answers are in.
About Mount Hill
Mount Hill is a suburban area located inland in Gloucestershire, with an elevation of around 105 metres. Mount Hill sits near the city of Bristol, approximately 4.2 miles away, and is close to nearby places such as Potterswood and Hanham. Mount Hill has a population of around 7386 people and predominantly consists of semi-detached housing. Mount Hill is also situated near Woodstock, and is about 102.3 miles west of London.
Fuel drain cover around Mount Hill and across Gloucestershire
The teams answering petrol in diesel calls around Mount Hill, in the BS postcode area, equally work the locations around it, Potterswood, Woodstock and Hanham among them. A forecourt, a supermarket car park, a lay-by or your own drive are all locations our technicians drain, and your car does not need to come to us.
Still at the petrol pump in Mount Hill?
Then you are in the best position there can be. Keep it off. Call.